I have not received the proper assistance with regards to my billing and am being charged a penalty fee for something that is not my fault

I have not received the proper assistance with regards to my billing and am being charged a penalty fee for something that is not my fault . I went to a Telkom In-Store and requested assistance to have my banking details updated so my debit order can go through. However my banking details were not updated and I tried to manually pay for my account as the debit order failed but was unable to due to faulty app and web assistance . I cannot be billed for something that is not my fault and have done all that I can to pay in time. When I tried calling the helplines my calls are never answered