Hello,

Even though you turned off that feature, QBO "might" still be placing a check mark in the credit in the RECEIVE PAYMENTS screen.  The credit should be visible under the invoices that are open and you just want to make sure if it is there, and you don't want to apply it, take the check mark OUT of the box.  That way it will just sit there in your customers account until you decide to use it on an invoice. (Or cash it in for a refund back to the customer)