You can delete a recorded payment from the invoice it was allocated to, or from Payments, in Bookem.
To delete payment from the invoice:
Go to Accounts - Invoices.
Select and open the relevant invoice.
Click the payment at the bottom right.
Click the Delete button.
To delete a payment from "Payments":
Go to Accounts - Payments.
Select the relevant payment.
Click the Delete button.
Read this article to learn how to void or delete an invoice.