Incorrect laptop received.

I was due for an upgrade and decided to get myself a laptop HP Core i3 11th Gen. I went to MTN Adderley street cape Town to order a laptop HP Core i3 11th which was in the pamphlet on special for 399 pm. The manager of the store Kashiefa told me that they don't have in stock. She gave me her number so that I can rather contact her instead of coming in every week for nothing after she keep on phoning the head office for stock only to find out they never had stock avaliable. I ordered a laptop by mtn online on the 29/3/2022.I repeated myself over and over that it must be the Intel core i3_11 Gen which is advertise in the pamphlets page 48 from Jan 2022 to March 2022.I received a intel (R) Celeron N4020 not what I ordered. Only to find out the incorrect laptop is advertise for R299 but they still expect me to pay 399 pm. I contacted them again and was told to speak to the retention dept. Spoke to Sandie Majala on the 14/4 and was told that he will cancel the incorrect laptop and send the coreect one. +- 2hours later he phones to say he cannot finalize the deal as they don't have stock. I ask him to get a manager to contact me. I did numerous call up to date no respond. Coming month end I pay for something I did not receive.so how do you advertise a special from Jan to March and you don't have stock. To crown it all the same laptop is again in the April pamphlet. Still no stock.