Wrong Pc Specs than what was advertised

Yesterday e went to the store to specifically upgrade to a laptop that has a Dedicated GPU. We were told that we are not allowed anymore to apply for a Laptop that has greater value than R9999 so we settled on one that was in that range, On the adverti*****t it said that the Dell 3543 I5 would have a Geforce 840M GPU just to find out that it has a 820M GPU now for me that makes some difference especially for the use that I need it for. Please note that I will take this further as I drove from where I stay to Vodaworld and I do not feel like this is a \small"printing mistake. I have already signed a contract for the wrong Laptop. Please would someone contact me to rectify the issue at hand"