Complain

I have been having telkom sim card for data only contract and it's more than 4 years, I was charged extra money apart from my debit order amount as it was fixed amount for 24 months. Now I was over charged by R221 and I logged a case with telkom and was told they can't reserve the money,now when I check they are still going to charge me another extra R231 again this month. Is this how telkom is starting to run there business