Dishonest contracts. Forcing clients to be in debt against their will

I have had the worst experience with cellc I can celled my contact in Aug requesting to be moved to perpeaid then it's was done revived confirm sms on both contracts they debited they last installment today then. They say the reversed the cancelation of one of the contracts how do they do that literally I am being forced to stay on a contract I cancelled cellc is dishonest and when I called in they say I missed a payment I sent them proof of my bankstatement showing all months have been paid cellc is dishonest they don't want to end contracts they want to keep people in debt so they can ruin our credit scores I advise the entire South Africa do not take out a contract with cell c