Very Bad service MTN South Africa

I am very disappointed with MTN South Africa , I got an E-mail in June 2020 that my contract was eligible for an upgrade , I called MTN and was informed that they did not have stock of the laptop that I wanted to upgrade to. Ref nr for the call:*** I have been calling them every month since then , just to hear they don't have stock , then on the on the 14th of October 2020 I logged a complaint on the MTH customer complaint website *** about this issue of FALSE ADVERTISING , AND LACK COOPERATION!!!!!! I got feedback that they are sorry but they cannot do anything about it. December 2020 the same deal was advertised again , I called but still no stock. on 5January 2021 I called MTN Upgrade department for the second last time and was informed that they indeed did have stock (15 laptops) on the HP I7 laptop that I was looking for but they did not have the Router that was supposed to be included in the deal , I asked the consultant if we cannot send me the laptop so long then afterwards they could send the router . I was then informed that they are not allowed to do that , and that I must phone later in the week again to do the upgrade. I again called MTN upgrade dept. on the 11 January 2021 and again they do not have stock. How can MTN South Africa advertise a product in the catalogue if for 6 out of 7 months they do not have stock. this is very unacceptable and I am thinking on cancelling this contract and moving over to CellC or Vodacom because this is not acceptable.