This reminds me of an experience I had in the UK that was not pure joy. I paid using their website, and as soon as I saw the payment confirmation appear, closed the web browser. Well, whatever tech they were using must have sent the internal “they paid” message on a hit from the confirmation page. So, the money came out of my account but their systems didn’t track it. It took quite a few weeks of back and forth to get my double payment back.