Clearing a vendor overpayment

I'm the lowly treasurer for a local non-profit. I get all the paperwork delivered to me monthly for posting.

Sequence of prior month transactions:

1. received an invoice from Vendor V for 0.
2. I recorded it as a payable
3. I cut a check for the balance due which cleared the payable. The check has cleared through the month-end reconciliation

This month I learned that the person who ordered the item had already paid for it with a $200 charge on his credit card, and will consider it as a contribution – i.e. no refund to him.

Meanwhile this month, the vendor sent us a refund check for $200.

Now I'd like to unscramble and post this in such a way that the $200 refund check shows up in the “Deposits” list, so I can show it in our cash receipts.

Suggestions welcome