Bank scam

They tell me from "Amazon" that I made a big purchase. I don't even have an Amazon account but that's how my mom fell for it. She called the number attached to the SMS and was about to be scammed. Everything seems to be with the bank, they say they call you from the bank and guide you to give out information, even to enter your card details so they can "deactivate" it. They even have the official sounds of the bank.