overcharged for a service i didnt even use

i checked my account and realised i was over charged i called to find out whats happening on my account the lady i spoke to said there was nothering that can be done but she will log a query with the billing department i called again as i was not happy with explaiation i recieved and i spoke to another lady who transfered me to the billing department i then spoke to a lady by the name of Evangeline who said they will credit my account and by amount to pay will come down . Today a lady from billing calls me and says they cant do anything to correct my account but they will give me the data that they took away i informed her that i spoke to a lady Evangeline who said my account can be credited as i do not want the data she said theres nothing that can be done and there is no lady by the name of Evangeline i not happy at all with the service im recieveing from CELL C their staff is not willing to help and they charge for benefits that i have not even used and then tell me nothing can be done about it ,this is unacceptable