TELKOM IS REALLY DISSAPOINTING

So on the 17th of January 2019 i changed my banking details with a call centre agent Veronica which according to was done with no issues, by end of February my account was debited onto the old bank acoount which is no more in use. So on two occasions i've spoken to a Mbali and a Miriam and i was given a case number and both confirmed to me that i am NOT at fault and that the call centre did not do what they are supposed to do. Now my account are in process of being locked and no one at Telkom is making an effort to come back to me with any answers. On 14th March 2019 i phoned again to gain answers, spoken to Andile and she made is sound that i am at fault the more i explained to her i am not at fault she is telling me something different. I am coming to the conclusion that there is no communication whatsoever between call centre agents and billing department, so when you as customer phones for answers they makes it feels you are at fault where you as customer do what is required, so when account is locked due to their fault customer must just accept it and move on from that.