Cell C SO UNPROFESSIONAL AND ******!!!

I had 3 contracts with Cell C, 2 cell phones and 1 month to month data and i finished the 1st one in february. and when the 2nd cellphone was ending they started calling me to upgrade and told them I won't because I've nothing but bad experience with them. And i also want an iPhone which they do not have and its been years being promised the same thing. They would call almost everyday and u would tell them no, when the contract ends I won't be continuing with them. Last month of the cell contract one lady called and i told her the same thing and she understood ... I then reauested she cancels the contract as its my last month and also cancel my data as i find it very expensive and she agreed. Next they continue deducting on my account and i disputed it. The first month it happened I told them to stop and when i spoke to the guy he is rude and denies anything being canceled... I was previously paying R1343 of which was too much for my financial state... And they are now billing me around R5500 now yet i keep explaining myself... Where am i supposed to get that money and why dont they want to cancel my contract? Why is Cell C so unprofessional though!!!!