Bad customer service

I specifically asked that my bank account details be updated on the 16th of April 2021 so that my smart devices would be debited from my Easy account, I was told that the request was approved and my bank details were updated on the system. This morning I discovered that they debited the wrong account resulting in failed debit orders. How many times must I call FNB or deal with unpaid debit orders when I made provision from my side. I am really tired of the **** service that I am receiving from FNB due to human error and incompetency. I better not be charged unpaid debit order fees this month