CUPIA - Customer Payment In Advance are different, you have to do a credit invoice first.

From V9 Help:

Rollback Complete Payment

Explanation

The Rollback Complete Payment activity is used to delete an entire payment when the payment is incorrect. All installments, invoices and payments on account that was included in the payment are set as unpaid and a voucher is created in the hold table in IFS/Accounting Rules. The voucher contains postings that reverses the postings on the original voucher. Any difference item invoice associated with the payment will also get cancelled. If a payment receipt has been printed, update the receipt status to Cancelled, but if the receipt is still in the Created status, it should be removed. If a receipt has been printed for a payment, it is not possible to make a partial rollback of that payment. In this case, it will be required to perform a complete rollback. 

Prerequisites

• The payment must exist.
• If the customer payment that you want to rollback is connected to a prepayment-based invoice, it is necessary to create a credit invoice for that invoice in order to rollback the payment.

System Effects

As a result of the Rollback Complete Payment, all installments, invoices and payments on account that was included in the payment are set as unpaid. Any difference item invoice associated with the payment will also get canceled. A voucher with postings postings that reverses the postings on the original voucher are created into the hold table in Accounting Rules.

Window

Customer Payment Rollback

Related Window Descriptions

Customer Payment Rollback

Procedure

To enter a rollback complete:

1. Open Customer Payment Rollback window. Use the Query or Populate function to find the payment or payments you want to work on.
2. Select the payment. You can select only one at a time.
3. Right-click and then click the Rollback Complete Payment operation.
4. If you choose Rollback Complete Payment, Rollback Complete dialog box is shown with the fields Voucher Date, Period, User Group, and Voucher Type. Check the voucher date and change it if necessary, then select OK. 
5. You can cancel the function here by selecting Cancel. If you do so, Customer Payment Rollback is redisplayed. 
6. After you have saved, Message is shown with details of Payment Series, Payment ID, Voucher Type, Accounting Year, and Voucher No. When you are satisfied with the details, select OK. 
7. The payment now has the status Complete Rollback, and a further payment is generated automatically for automatic posting with the status Rollback. Also, an adjustment voucher for the payment is generated.

The other possible reason of this issue is that you are trying to rollback payment of advance received from customer, where advance is already used in amortization of delivery invoice - in such a case you should first rollback the offset payment where this advance is used, and only after that you will be able to rollback the initial advance payment.