How you amend cash received wrongly allocated to customer

Hello Userjreid, 

Welcome to the Community page, 

So what you need to do to resolve the issue you are currently having is don't void just delete the record payment, then reallocate the payment to the correct customer and then rematch at the banking page. If the bank has been reconciled it will put your reconcile out so you will need to add the amounts back into the reconcile.