2 weeks old contract and the pone has not work

I am a new client of MTN. I have app**** for a new contract 2weeks ago and have received my new phone from MTN Maponya mall on the 1st of July 2020. everything was ok when I received the phone. however, an hour later I could not make calls not check balance. I went back to the store and they told me they have restarted my services and it should be ok within 72 hours. 72hours later nothing happened still. I then contacted the activations department and only to find that my sim card is the problem as was instructed to remove my sim and put it in another phone and it still didn't have network. I went back to the store for a new sim card. I got a new sim and was told to insert the following day, I did that and till this day this phone is not working cant make calls, can receive some calls not all. I am so disappointed about this network that you call the BOZZA network. I want this contract cancelled with immediate effect