If you want to find out who a specific receipt was allocated to, all you need is the transaction number.
1. Find the transaction number
Transaction number of a cash book entry. The DP = Debtor's Payment
2. Go to Platform > Debtors > Receipt a Payment
3. At any customer, select the 'Find Transaction" button and enter the number. Eg DP33405
4. If that transaction exists in the Debtors Ledger, the customer's records will appear.