Incorrect Debit by the bank

Nedbank debited multiple accounts with R156(desc:NRB accting subscription fee) in the beginning of the month(the 1st) and I phoned them immediately on the 1st or 2nd of Feb the first time to find out what it was for. They reverted and apologized that it was a mistake on their side and a call was logged (ref ***8). Unfortunately they have still not explained exactly why this happened and my money has not been credited. One would think that to avoid reputational damage and losing clients they would sort this out with ASAP. I keep phoning and they keep not giving me an answer as to why this happened and when they will pay the refund. Who knows on how many accounts this happened and if they will even reverse it if people do not pick it up? <br> <br> Please escalate properly and give me some feedback Nedbank!