Worst service and discrepancy with Cell c

I had a cellphone contract with Cell c for 24 months and it supposed to have ended, end of June 2015. Then I was on month to month contract that I was not aware of because none of the people from Cell c even contacted me and advised me about that new contract until I called customer service and they advised me. I then cancelled the contract on 3/08/15 then was advised I would be billed for the 3 days that fall into September. 28/09/15 cell c debited R104.99 from my bank account. Now cell c sending me emails and calling saying I didn't pay. If you can email me saying I haven't paid you, why couldn't you email me and inform me about the month to month contract. ?Im frustrated with this company and what exactly am I owing you if you have deduced