Lack of Assistance

I took out a Cell C fibre contract when the special was running (first 3 months free- April, May, June) end of July i was supposed to be debited for my 1st month and Cell C says i was debited and my balance due was R0 yet nothing was reflecting on my bank statement showing the debit order transactions. Once again my account was debited for end of August - i called today to query why they arent debiting my account and they said they couldnt give me an answer because i failed to pass the security questions (this cannot be possible as i am 100% sure of my name, ID number, Address etc...) . The lady at cell c said i need to go to a cell c store to sort this out (which is inconvienient for me as I do not have time). My statements are also reflecting different amounts each month when it should be R899 uncapped, 20mb line up and down. The fact of the matter is that i am trying to pay for something that i am utilising and they cannot assist me at all. The quality of service has been shocking and I am extrememly dissapointing in the service that i am receiving especially the fact that this is my first contract with Cell C. I am at the point where i am starting go regret taking out this contract with Cell C.