diff --git a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
index fc5ca170a..14c5b350b 100644
--- a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
@@ -22,10 +22,12 @@ import {
   createContribution,
   updateContribution,
   createTransactionLink,
+  confirmContribution,
 } from '@/seeds/graphql/mutations'
 import { listTransactionLinksAdmin } from '@/seeds/graphql/queries'
 import { ContributionLink as DbContributionLink } from '@entity/ContributionLink'
 import { User } from '@entity/User'
+import { Transaction } from '@entity/Transaction'
 import { UnconfirmedContribution } from '@model/UnconfirmedContribution'
 import Decimal from 'decimal.js-light'
 import { GraphQLError } from 'graphql'
@@ -142,6 +144,8 @@ describe('TransactionLinkResolver', () => {
       resetToken()
     })
 
+    let contributionId: number
+
     describe('unauthenticated', () => {
       it('throws an error', async () => {
         jest.clearAllMocks()
@@ -311,7 +315,6 @@ describe('TransactionLinkResolver', () => {
           })
         })
 
-        // TODO: have this test separated into a transactionLink and a contributionLink part
         describe('redeem daily Contribution Link', () => {
           const now = new Date()
           let contributionLink: DbContributionLink | undefined
@@ -337,6 +340,10 @@ describe('TransactionLinkResolver', () => {
             })
           })
 
+          afterAll(async () => {
+            await resetEntity(Transaction)
+          })
+
           it('has a daily contribution link in the database', async () => {
             const cls = await DbContributionLink.find()
             expect(cls).toHaveLength(1)
@@ -378,6 +385,7 @@ describe('TransactionLinkResolver', () => {
                 },
               })
               contribution = result.data.createContribution
+              contributionId = result.data.createContribution.id
             })
 
             it('does not allow the user to redeem the contribution link', async () => {
@@ -513,6 +521,92 @@ describe('TransactionLinkResolver', () => {
           })
         })
       })
+
+      describe('transaction link', () => {
+        beforeEach(() => {
+          jest.clearAllMocks()
+        })
+
+        describe('link does not exits', () => {
+          beforeAll(async () => {
+            await mutate({
+              mutation: login,
+              variables: { email: 'bibi@bloxberg.de', password: 'Aa12345_' },
+            })
+          })
+
+          it('throws and logs the error', async () => {
+            await expect(
+              mutate({
+                mutation: redeemTransactionLink,
+                variables: {
+                  code: 'not-valid',
+                },
+              }),
+            ).resolves.toMatchObject({
+              errors: [new GraphQLError('Transaction link not found')],
+            })
+            expect(logger.error).toBeCalledWith('Transaction link not found', 'not-valid')
+          })
+        })
+
+        describe('link exists', () => {
+          let myCode: string
+
+          beforeAll(async () => {
+            await mutate({
+              mutation: login,
+              variables: { email: 'peter@lustig.de', password: 'Aa12345_' },
+            })
+            await mutate({
+              mutation: confirmContribution,
+              variables: { id: contributionId },
+            })
+            await mutate({
+              mutation: login,
+              variables: { email: 'bibi@bloxberg.de', password: 'Aa12345_' },
+            })
+            const {
+              data: {
+                createTransactionLink: { code },
+              },
+            } = await mutate({
+              mutation: createTransactionLink,
+              variables: {
+                amount: 200,
+                memo: 'This is a transaction link from bibi',
+              },
+            })
+            myCode = code
+          })
+
+          describe('own link', () => {
+            beforeAll(async () => {
+              await mutate({
+                mutation: login,
+                variables: { email: 'bibi@bloxberg.de', password: 'Aa12345_' },
+              })
+            })
+
+            it('throws and logs an error', async () => {
+              await expect(
+                mutate({
+                  mutation: redeemTransactionLink,
+                  variables: {
+                    code: myCode,
+                  },
+                }),
+              ).resolves.toMatchObject({
+                errors: [new GraphQLError('Cannot redeem own transaction link')],
+              })
+              expect(logger.error).toBeCalledWith(
+                'Cannot redeem own transaction link',
+                expect.any(Number),
+              )
+            })
+          })
+        })
+      })
     })
   })
 
diff --git a/backend/src/graphql/resolver/TransactionLinkResolver.ts b/backend/src/graphql/resolver/TransactionLinkResolver.ts
index d6e8e09ae..9e365ab51 100644
--- a/backend/src/graphql/resolver/TransactionLinkResolver.ts
+++ b/backend/src/graphql/resolver/TransactionLinkResolver.ts
@@ -285,12 +285,20 @@ export class TransactionLinkResolver {
       return true
     } else {
       const now = new Date()
-      const transactionLink = await DbTransactionLink.findOneOrFail({ code })
-      const linkedUser = await DbUser.findOneOrFail(
+      const transactionLink = await DbTransactionLink.findOne({ code })
+      if (!transactionLink) {
+        throw new LogError('Transaction link not found', code)
+      }
+
+      const linkedUser = await DbUser.findOne(
         { id: transactionLink.userId },
         { relations: ['emailContact'] },
       )
 
+      if (!linkedUser) {
+        throw new LogError('Linked user not found for given link', transactionLink.userId)
+      }
+
       if (user.id === linkedUser.id) {
         throw new LogError('Cannot redeem own transaction link', user.id)
       }
diff --git a/backend/src/graphql/resolver/semaphore.test.ts b/backend/src/graphql/resolver/semaphore.test.ts
index 70e3e5f96..b3c99ba7d 100644
--- a/backend/src/graphql/resolver/semaphore.test.ts
+++ b/backend/src/graphql/resolver/semaphore.test.ts
@@ -191,4 +191,50 @@ describe('semaphore', () => {
     await expect(confirmBibisContribution).resolves.toMatchObject({ errors: undefined })
     await expect(confirmBobsContribution).resolves.toMatchObject({ errors: undefined })
   })
+
+  describe('redeem transaction link twice', () => {
+    let myCode: string
+
+    beforeAll(async () => {
+      await mutate({
+        mutation: login,
+        variables: { email: 'bibi@bloxberg.de', password: 'Aa12345_' },
+      })
+      const {
+        data: { createTransactionLink: bibisLink },
+      } = await mutate({
+        mutation: createTransactionLink,
+        variables: {
+          amount: 20,
+          memo: 'Bibis Link',
+        },
+      })
+      myCode = bibisLink.code
+      await mutate({
+        mutation: login,
+        variables: { email: 'bob@baumeister.de', password: 'Aa12345_' },
+      })
+    })
+
+    it('does not throw, but should', async () => {
+      const redeem1 = mutate({
+        mutation: redeemTransactionLink,
+        variables: {
+          code: myCode,
+        },
+      })
+      const redeem2 = mutate({
+        mutation: redeemTransactionLink,
+        variables: {
+          code: myCode,
+        },
+      })
+      await expect(redeem1).resolves.toMatchObject({
+        errors: undefined,
+      })
+      await expect(redeem2).resolves.toMatchObject({
+        errors: undefined,
+      })
+    })
+  })
 })
diff --git a/backend/src/seeds/graphql/mutations.ts b/backend/src/seeds/graphql/mutations.ts
index 69d6d16d8..1aa12a32f 100644
--- a/backend/src/seeds/graphql/mutations.ts
+++ b/backend/src/seeds/graphql/mutations.ts
@@ -89,6 +89,12 @@ export const createTransactionLink = gql`
   }
 `
 
+export const deleteTransactionLink = gql`
+  mutation ($id: Int!) {
+    deleteTransactionLink(id: $id)
+  }
+`
+
 // from admin interface
 
 export const adminCreateContribution = gql`