I have an invoice and a credit that show up on my aging for a customer.  When I go to AR-C to apply the credit to the invoice, the invoice is not there.  Both of them are dated the same date, so that is not the issue.  Any solution to this?

It was put in as a  larger deposit and this is the balance.  When I look in AR-N it doesn't show a sales order number that it is linked to.  It tells me that I can't delete it because it has been partially paid and I have to do a refund or enter a voucher.  I have tried both of those methods and failed.  How do I disassociate it from a sales order?