Poor Service Cell C

Since day one that my contract was given to Cell C after Glocell sold it to them, I just had no nice experience with Cell C at all. Firstly they never correctly activated my insurance on my cellphone, they day it was ****** I only find out about it. Ever since I as a customer phoned and requested it to be cancelled this was in June was still every month I get billed for it. After numerous calls to them and visiting the branch still not cancelled. What kind of services is this? Another thing how can you sign a contract for an x amount monthly but when it comes to payment it is almost triple the amount without any proper answer or explanation. This is now services that anyone should have or experienced.