Deal with free gift gone wrong

I got the Huawei MediaPad T5 10.1" for R199 pm on the 22 December 2018. In the December brochure they advertised clearly that you get a black fold-over cover for your tablet for free. On the day of getting my tablet, they did not have the cover (how do you advertise that you get a free gift with a specific deal, and not have the free gift in stock?). They promised that it will arrive the 2nd of January. I only got it yesterday (10 January 2019). What a big dissapointment. Then secondly, it was a whole different cover. It was not a fold-over. It was a clear cover. How am I supposed to protect my tablet with that? When I asked about why I got a totally different cover, they said that they have been struggling with Huawei, and are unable to get the covers that was advertised. This is unacceptable. I need a fold over cover to keep my tablet protected. Why would you advertise something and give something totally different? No one told me beforehand that the tablet cover does not look like the one they are advertising. A cover for this tablet is very rare and close to impossible, so where will I get a fold over cover for my tablet now? I am supposed to pay extra for something that is clearly supposed to be free for that month's deal? The staff did not even look bothered about the fact that they are "struggling" with Huawei's suppliers. NOT happy with the false advertising, NOT happy with the service.