Non existing service - change of bank details impossible to get done

After calling, and confirming change in bank details, I am still getting debit orders going through account that is no longer active. Now I am unable to get through, as the bank is constantly too busy to answer, and of course charges are ridiculous, which I will be responsible for. Can someone please contact me to get bank details changed, so it actually is done, and not a waste of my time and money. I want my charges refunded. Thanks