Bad service

Good day My name is Daniel, I have an american swiss acount which is a tfg group, my problem however is that this company is **********, I have two plans on this account, or used to have two plans, 6mnths and 12mnths, the 6 mnths account is paid up yet I am being billed an amount of R16-94 interest on this specific plan, also these people change plans duration to suit them, for instance, I have paid a total of 9 months on the 6 months plan, and I have paid more than the amount due, double on some months, same with the 12 month plan, this plan is almost paid up, but will end up paying 15 months Plaese note, my acount is and was not in arrears I feel these people are commiting ***** to generate moneys by extending plans and some moneys disappears Im fed up with these people Please help, they do not come back to me as promised, I have raised this issue with them