I hope you saved what you could from that exchange, as well the attempts to contact them. If they ever notice, their AI mistake will become your problem to deal with, (and the kind of news story to end up on a Steve Lehto video).

If that happened to me, I’d have a chat with my bank, “please help me return this money to where it came from, it was payed in error. They have no way to contact a human and I don’t want them to accuse me of fraud down the line”.