The sales here are divided by different types, therefore almost every customer has 2 subaccounts but the customer pay us all invoices in one check.  
 
When posting payments one of the checks had a payment for 2 invoices (same customer subaccount 1 and subaccount 2). Before aplying payment to the second subaccount (I normally divide the check in two amounts) the diference was taken as overpayment. At this point I have no way to apply this credit amount since later on I applied payment to the second invoice for subaccount 2. Therefor I have an extra amount in the checking account and a credit amount in the AR aging.
 
I know that is confusing but I have no idea how to fix it and how to post those payments considering the way sales are oriented and how everything has to be posted using sales module.  
 
thanks  
 
 
 

I do have the option of applying to other customer. I saw that after the mistake.  
 
I fixed the problem using AR-M I tested it before to see how it worked and I am back in the game now.
 
Thanks for your help.
 
Irma