Most useless network ever

I've never had a satisfying experience with Cell C. From my first day It was just badluck and it continues. My scenario is as follow. Being gatvol for poor service and very poor network reception I've decided to buy myself out of my contract for the second time. I pboned Cell C and got an settlement amount of R645. 83. I Paid the full amount on 02/02/2018. I was told that if there is still any amount outstanding it will go of at end of February. Nothing went of. Now I got a statement from InfoSlips that there is an amount outstanding for R388. That is way more than the monthly subscription. And further more another R754. 84 outstanding. How is this possible? We got confirmation sms to show all is canceled. I even gave my monthly bemefits up to cancel this contract. How much more must I pay and why more than the outstanding contract amount? I will never suggest Cell C to anyone. I hate this network that only rips off people, with a passion.