Poor customer experience

I Have a contract with MTN and had issues with paying for since I lost my job but as soon as I got a new job my contract was already deactivated my number was no longer making calls or receiving calls, so I contacted MTN customer service to fix that and continue paying for my contract it's been more than 7 months no one is able to help they keep telling me my contract is with old system and they can't access it or give me a number to the department they all offer to transfer the call to whoever is not available or the line do not exist I hold for hours daily with no help. I tried paying direct to MTN using my cell No as reference yet still my credit score still shows MTN contract is in arrears from the last time we had a good agreement.