Cell C needs to pay my refund

I had a contract with Cell C which I took on February 2019. January 2020 my contract was handed over to the lawyers. And I had to pay the outstanding amount of R5850 for the next 10 months which was R585 per month. I paid this monthly fee from January and in August, 2 months before the contract was suppose to end I paid the settlement amount which was more than what I was suppose to pay. They have been debiting the R585 for the past three months. I’ve been calling them since asking why are the still taking the money if the account has already been settled. They’ve been telling me they will call me since November and December unfortunately they debited a further R140. So in total they need to refund me R1895. I am sick and tired of calling everyday and nothing gets done. I am forever waiting for a call from Cell C to refund me my money. I am honestly not happy with the service I received. They will probably debit again in January for the 4th time. I don’t even know who to call and what to do now to get my money.