Hi-fi Corporation
Staff dont know how to add a debit orde

I changed my bank account, and got a letter from the banks to give hifi corp showing my new bank details.
I take it in to be changed and they said i missed a payment so i pay for that missed payment, and ask for my bank details to be changed, the very next month my debit order doesn't go off and i have to go into the shop again to ask them to update my bank details and pay again, the promised me that the bank details were changed. the 3rd month the debit order didn't go off again and i had to go in to find out that head office deleted my debit order and i had to pay more than my normal monthly instalments due to interest or something. and reload my debit order for the 3rd time. (Waste of my time)
WHY MUST I PAY MORE FOR MISTAKES OF HIFI CORP STAFF NOT KNOWING HOW TO DO THERE JOB!!!