X card not lining up with specials

I purchased 2 x 2L Pepsi which was advertised 2 for R30 at the time of purchase (8th Dec 2020) for X card users. I was charged full rate despite having my X card swiped. There was no advertised limit of 1 special per customer printed, in any event I ought to have been discounted at least on the first set of 2 bottles. Either the system cant register multiples of 2... or the X card is not synced up with specials. i got ****** for rands I cant use now. Everyone is trying to take their money as far as they can and this system is not charging advertised prices...