If an invoice is overpaid, then the invoice will end up with a negative balance due or a "credit".

The credit can be refunded to the insured or applied as a credit to another payable or invoice.

just select Issue Refund and in the notes specify if a refund check was sent or the balance applied to another invoice.

If the credit balance was applied to another invoice, then reference the credit in the payments for that invoice.

Thank you!