Changed to EFT and still got debited

I WOULD LIKE TO LODGE A COMPLAINT FOR YOUR BILLING DEPARTMENT! I CHANGED MY DETAILS AND TOLD THEM I WILL PAY VIA EFT EVERY MONTH AND THEY STILL DEBITED MY ACCOUNT! IF YOUR CALLS ARE DAN RECORDED CONFIRMING THAT THIS WILL BE PAID VIA EFT WHY DID YOUR BILLING DEPARTMENT DEBIT MY ACCOUNT !!! I WANT THIS SORTED OUT IMMEDIATELY AS I DID NOT GIVE PERMISSION FOR A DEBIT AND I WILL TAKE THIS UP WITH A LAWYER IF IT IS NOT SORTED OUT IMMEDIATELY!!!