Cell c contracts big ****

Cell c contract are big **** ***** i paid the remaining balance for my contract in advance since my contract was about to end then after I cancelled and I received a cancellation sms confirmation now they keep on trying to debit money from my account claiming that I owe them and when I went to one of their branches and even called them they claim that the money I paid in advance does not reflect from their system but some consultants says they can see it I then send proof of payment to this email *** it says their mail box is full try again later I’m sick and tired of these ***** just because I don’t want to renew with them then they try to ***** my money sis