Returned phone

I hereby lay a complaint against MTN. In January 2020 this year, I upgraded an iPhone 11 at MTN over the phone. The phone was delivered around the 10th January 2020. I started to experience problems with the phone because it failed to connect to the network. I therefore reported the phone to MTN however MTN sent a DSv courier on the 17 March 2020 to collect the phone and promised me will send me a new phone. Till today I haven't receive any communication to MTN I am the one calling them and everytime they told me that the warehouse is not responding yet about the phone. My biggest worry is that its been two months now and MTN is not giving me a direction of what is happening. I would like Hello Peter to help me with cancellation of a contract because I am not happy to pay for something that I don't have. I tried to be patient enough and I also understood that there was a total lockdown but my confusion is that MTN is still waiting for response from the warehouse and I don't know how long this will take.