I overpaid a vendor

I overpaid a vendor

I am busy uploading my historical data into my Zoho Books.

In 2010 I over paid a vendor for a bill. How do I record this over payment, when I try and record the payment I actually made Zoho will not let me make a payment greater than for the bill outstanding. How do I record this over-payment and still have credit available for future payments to this vendor?