Poor customer service

I was appalled by the service I received from a store consultant on Wednesday, 11th December 2019 from the mtn store at Cornubia. I signed up to a new mtn contract for the P30 lite. I was told I had to pay R115 for the sim card whether I was porting my number or not. I did return to the store on the 13th of December 2019 as I wanted to cancel the deal since I was unhappy with the extra charge and was also unhappy with the colour of the device. I was told I could not cancel as the service is already active, yet I did not receive the phone and the only time I would be able to cancel if if there is a fault with the phone. I was told that I will receive a call back from the guy I signed up with, yet I am still waiting. I am totally disgusted with the level of service I received and I just want this contract to be terminated.