When will I receive my refund for rejected Stripe Credit/Debit payment?

This refund went through in the form of a reversal. In the case of a reversal, you won't see a refund credit on your statement—you'll just see the original authorization drop off your statement entirely after a few days. There will be no payment and no refund. It'll appear as if the whole transaction never happened. Your bank should be able to confirm this for you.