Be careful who you sign contracts with, you might end up like me!

I have a contract with MTN which I have had for several years. My contract was due to end at the end of April, 2018. I decided that I no longer wanted to have a contract but to go onto "Pay as you go'. I went to the MTN shop in the Herm**** Mall to tell them I did not want to renew my contract and that I wanted to go onto pay as you go, only to be told that they were not able end contracts and I was give a number to phone. FOR THIS REASON, I was forced to phone to cancel the contract. So, on 19.4.18 I phoned and spoke to Sipelele who gave me the reference number ********** 50. He then put me through to another number where I spoke to Banele, ref no. ********** 61. I told him that I wanted to cancel my contract and he told me I would receive notification thereof in 3 days. Three days later I got a notification congratulating me on my new contract! Since then I have been back and forth to the shop in the mall, they have written 3 letters to the head office, one of which I was give the ref no # ********** 7, 'Retentions', (whatever that means...) the letters were sent on 20.4.18, 23.4.18 and 11.5018'... and I have phoned numerous times all to no avail. in the meantime I sit with this new contract, which I DO NOT WANT,( which I hear ends in 2020) and about which I know NOTHING, don't even know what it involves and for which I have not been offered a new phone.....which I obviously don't want... and I continue to pay. I have not signed any contract, have not even seen a contract. I just want this all to end so I can be free of this ***********, sly company.