Cancelled contract still debiting

I’m so angry cell c is greedy I cancelled my contract last year June and cancelled the line but now I’m being harrased by debt collectors from new debt saying I’m owing cell c to make matters worse they are still debiting my account and initial my contract was R189 but the debit is R289 on Monday I tried calling the legal department was put on hold for 30 min I even ran out of airtime I’m sick and I’m tired I even changed banks because of them they will reimburse me coz now I can’t close my Absa account without settling R600 I will not pay it and that time it’s affecting my credit score no more will I ever do business with celll c it’s bn long fighting this case nothing being resolved selfish ******