Checkers Xtra Savings Xtra Ready to Fire an Employee for Incorrect Cash Up?

So this is my experience, and flag it if it sounds strange.

10 days ago I'm at Checkers Hilton and I swipe the savings card that I had on me. I happened to have my ex-partners savings card on me and she phoned me confused because she was getting calls from Hilton Checkers about an issue. I finally received a call from Checkers Hilton telling me that the cashier had accidentally given too much change and that I needed to pay this back. I was told that failing to make payment would result in the employee being fired which I'm fairly sure if it's a first incident would be against the Basic Conditions of Employment Act? told them that I had no issue with making payment (I had no idea I'd received more change than I was meant to as I was talking with a friend at the time) but could they please send me their Checkers confirmed banking details of which I am yet to receive. My question is this though, is a local branch allowed to use the personal information on the savings programme to contact customers in such a way and can you tell a customer that the employee will be fired otherwise for a first offence?