Double payments can be identified using two methods, depending on whether or not the customer used the bank reference code when paying the sales invoice.
1. The customer has paid the entire invoice using the bank reference code, and the invoice has been marked as paid. The customer then makes a second payment using the same bank reference code. This payment will not be allocated to the invoice, since its status is already Paid. Thus, the payment in the reference data will not be allocated or signed as OK. These cases can be quickly checked from the Reference payment clearing report (Payment reports), which includes all payments received within the specified period of time that have not been allocated automatically. You can also search for payments by sum from the report, or from the Bank statements and reference payment report that includes all received reference payment data.
2. The customer has paid the invoice and the invoice has been marked as paid. The customer makes a second payment without using the bank reference code. This payment will only be shown on the bank statement (i.e. reference data has not been received from the bank) and can be found from the statement.