MTN - MY THIEVING NETWORK

3 Weeks ago i took a laptop from MTN on my upgrade (Lenovo Yoga) i was not happy with the product as the brand new laptop did not work. Applications didn't respond and the laptop connected to wifi networks then just stopped connecting all together, this happened in less than 4 days. The laptop was returned to the store before the 7 day period where I asked to change it for something else and the store refused, they sent me on a wild goose chase to have the laptop set up and checked in Clearwater mall but there wasn't anyone who could assist me. I then went back to the store I got it from ( MTN in the Wesbank building and they then said they will have to book it in which they haven't. I have called the call center, head office and various stores who all have given me different information regarding this matter. I DO NOT WANT THE PRODUCT THAT DOES NOT WORK! YET MTN WILL NOT EXCHANGE IT FOR SOMETHING ELSE? I have gone as far as trying to then cancel the contract and they have advised the penalty would be to pay the 24 months up front for a product that doesn't work? IF THIS ISN'T **************** I DON'T KNOW WHAT IS! I still have the laptop and they refuse to help me!