HELP: How to reverse a refund?

[east_bay_commissary]

Basically, my tracking number didn't update for a week on USPS for some unknown reason (it was priority mail, too, makes me kind of mad). I refunded the buyer his money just yesterday, by cancelling the order. How do I cancel the cancellation now?

[couldabeenworse]

You can't.  You need to ask the buyer to send another payment.