MTN not delivering on deal....MTN owes me a tablet

Let me begin with a bit of background. End of September i went to the MTN shop in Kimberley to upgrade and wanting the promotion advertised with a Huawei P10+ with free Huawei T2 tablet. They had not received any stock so i waited and after two weeks they still did not receive any. One of the employees advised that they put the request for MTN online to deliver it for me. Couple of days later i only receive P10+ by courier. The next day i contact the store stating the problem. They realized that a staff member selected the wrong option when order was placed for just the phone and not phone and tablet. They then wanted me to return the phone and wait for the phone and tablet to be sent to me. I was not willing to do this seeing as that have i have waited so long already. But i still expected my tablet as was advertised and requested by me. Now it is almost 3 months later....many many phone calls and inquiries made but no tablet. I feel that this is horrible service and MTN owes me "my tablet". Why must i be punished for a mistake made on their side? As i see it this constitutes as falls advertising and breach of contract.