Service totally unacceptable

This is by far the worst provider Ive ever used.. Please tell me why am I being debited after advising that I have changed bank details??? And not only that, there are extra charges that comes with the debit??? How are you Telkom continuing to debit on an account that Ive advised will not have money coz Ive changed my bank accounts?? Is this on purpose so that you add the extra charge for a "failed debit order"??? Are you deliberately ****ming your clients?? This is unacceptable.. It is very unprofessional and Ive never signed for this kind of treatment. I went in the store and they couldn't even help me because all this was arranged "over the phone" and not in store...I work very hard for my money and you think you can just milk it out ridiculously like that??? Have shame!!!