8ta call center is useless

I have been trying to get telkom mobile to help me solve the billing issues I have with them but they either not willing to help me or they are just do not care.

Telkom is debited my account on the wrong date and the debit was return because of insufficient funds then they charge me for that. When I try to explain that to the call centre agent all she could say to me is "sorry" they are charging a lot of money for the returned debit oder, they are going to do this again and charge me. I do not know what to do if the the call center can not help me because it is not fair it is a lot of money .