i have an hst bill that im looking to pay with an hst credit one is set to a vendor and the other a customer. is this possible?

Hi Mis Ter C, 

Welcome to Community!  QuickBooks Desktop is a versatile program for managing your work seamlessly.  I'll be happy to provide the information you need regarding the transaction for your customer.

Currently there's no option for for paying your customer by a vendor.  These types of transactions are recorded individually.  I recommend reaching out to your accountant for their expertise and best course of action.  If you don't have an accountant, you can easily locate one in your local area here.

Please don't hesitate to reach back out if you have any other questions.  We'd be glad to assist!

If I understand correctly, you under-remitted your Dec HST leaving a Vendor Bill to be paid. You say that you have a Jan credit for the same amount. How is this possible? you have not yet filed the Jan HST return. In any case, once you do file the Jan return and receive confirmation of a Credit, it should be entered as a Vendor Credit - the Vendor (Receiver General) was short paid in Dec and Overpaid in Jan. Now the Credit can be applied to the Balance owing in the Pay Bills window.