MTN bad service

On the 27th of February I did an upgrade for my son, which account is in my name. He got a Huawei P40 Pro device. The sales person at the MTN shop in Mall @Reds explained to him certain futures of the device and said that he could download the android system through the Pandora app. This did not work and he was not happy with the device. He called them on the 28th of Feb and was told that he cannot exchange the cell and they cannot do anything for him. After a couple of calls to them again he was advised that he must come and see the Huawei expert at the shop, which also did not work as the expert could not help. I called the MTN call centre on the 23rd of March and asked if i can either exchange the cell or cancel the contract. I was told, yes, but i have to go to the shop were i signed the contract. My son went there and was told that we have to call the MTN call centre. I then made another call to them and was again informed that i have to do it instore. They also said that if the store does not want to help me i must call them again. This in fact did happen and I was then told, while i was in the store, by the call centre that i cannot cancel the contract as it was supposed to be done after ten days of signing the contract. Why were we not informed when the first call were made on the 28th Of Feb. How can MTN expect us to use a device which we cannot use and they do not want to exchange it. The same happened to family that has Vodacom as their service provider and they exchanged the device within 1 week. I have been a loyal customer for more than 20 years and do not expect this treatment. Yello, NO where you go!