Horrific customer service and till ****s

I am being coned about R1200. 00. The teller(Dumisani Sithole) refuses to accept that she made a made a transaction of about R1200 instead of R479. She tried to cancel the first incorrect amount but unfortunately it was discovered that the R1200 went through as well as the R479. The bank notifications came through and ahe gave us a very bad attitude when we went back to the store to enquire about the amount and said it was not her problem that the transaction she tried to cancel after realizing she has put incorrect amount went through. She then phoned the bank with the attitude and the bank confirmed that the transaction went through and we must be refunded. She then phone someone and the name appeared on her phone screen was Dikeledi, she further conveyed to Dikeledi as if she is not the one who made that transaction as she kept on saying she only punched R479 and she is not aware of how the other amount happened. It is such a horrific experience and very poor customer service for someone to actually tell us that the transaction went through by itself, she doesn't even know where it was made.