Big mess with upgraded contract

Good Day I have 2 contracts with MTN. In July 2020 I reached my 24 month contract period. I phoned the call center to do an upgrade. I spoke to a guy by the name of Sipho. He did the upgrade for me and told me I will receive my phone within 3 days. 2 weeks later I did still not receive my new phone and phoned in again and they told me that the watch that comes with the phone is out of stock and they are not sure when the new stock is arriving. I then told them if that was the case I would rather then cancel the upgrade as at the time Vodacom had stock and was going to take the contract with them. 3 days after I told the call center to cancel the contract, I received a call from a courier company confirming my details for the delivery of the phone. I advised them that I have canceled the contract with MTN but they said they do not know anything about it and their instruction was to deliver the phone and watch to me. I then decided since they got the stock and ready to deliver I gave them my details for the delivery. I then phoned MTN again to tell them that they didn't cancel my contract as the new was arriving the next day, so they must cancel the cancelation as I will be taking the new phone. My new phone arrived with the watch and a new sim card. I inserted the sim card in the phone and everything was working perfectly. The very next day after the delivery of the new phone my number was canceled and put on prepaid. I then contacted MTN and told I canceled the cancelation and received my new phone why is my number gone to prepaid. They advised me that they will rectify the problem. It has been 3 months now and I have been to the MTN store at the Glen about 3 times and I have called the call center to rectify this problem numerous times and still nothing is fixed. What makes matters worse, is that MTN is now charging me for an early cancelation and billing about R10 000 for the new phone and watch. Also, MTN has now suspended my other number because of that bill. This is unacceptable. Please can somebody fix this mess? I have been trying now for 3 months running after you guys to fix your own mess and I am tired now. If this is not sorted within the next 3 days I will rather pack the phone and watch back in its box and return it to an MTN store and move to another network. Please can somebody who is really going to fix this problem call me ASAP to resolve this issue as all the other people I spoke to before were all bull****ters saying it will be resolved in 72 hours.