Poor Customer Complaint resolution

I was contacted by CellC on Monday after the weekend I had posted my review. Thanks lady I spoke to apologized and assured me the matter was resolved just when I was celebrating on Wednesday I got a call from the collections department stating I my account is in arrears. Now it's a daily phone call and I find myself explainig exactly the same thing.

I am tired and I don't know what further steps to take now to ensure this is resolved.

Your assistance will be highly appreciated.

Thank you