I sent a <1000 payment to misspelled version of the intended email, because it popped up first and I wasn't careful. This is not the end of the world, but it is annoying to have to let the payment sit there unclaimed for 30 days before it's returned.
I did search this thread and googled this question. A previous poster claimed to have canceled a transaction within a few hours but didn't provide details. My current search indicates that you can cancel a payment only from "authorized payments", but this payment wasn't set up that way.
If anyone has successfully canceled an AP payment, I'd like to know how to do so. If not, I'll just wait for it to be returned. Thanks.