No return accepted after 48Hrs

I bought a PC copy of the latest Batman game from CNA 18/07. I bought a retail copy at around R270 more than a digital version because of the size of the digital download. Needless to say,from the 5 retail DVD's supp****, only 7Gigs installed & it then wanted to download another 27Gigs,data I just don't have. The retail cover does not indicate a download is required. I went to CNA today to return the game,they refuse to accept it as they say that there is a 48Hr returns policy on games which isn't displayed anywhere or explained to the customer upon purchase,in fact, the person I was dealing with didn't even know about their 48Hr policy initially, its not even mentioned on their website! I was told that they are no longer liable & that I should contact the distributor (no details or name of distributor provided). I contacted another retailer of this game & they indicated that they don't sell this game because of all the technical issues with it currently,something I've also found out about only after my purchase by searching online.This is a responsible retailer, CNA is not, they should not be selling this & lumping the customer with the responsibility for their defective product.