Fonseca

When I create a new customer with a starting balance and add new invoices to the custumer's account, then when I receive a payment from the customer including the starting balance, the program applies the payment to the new invoices and tells me there's an over payment and ignores the starting balance even though it shows the correct total balance due in the custumer's list, how do I stop it from asking me to apply an over payment to a new invoice when it insn't any over payment?