Mt patrick did not explain to me about the product

I bought a PlayStation 3 at ok funitures and i was assisted by mr patrick.its space is 12 gig.i asked whether that 12 gig is the space for me to play the games he said yes i asked him will it affect me when i install the games he said no it wont.i then asked what does the space mean he then told me its just for the game to be faster. But now i went home and played it only to find that i have to install the game's before i play and one game alone is 11 gig.so on monday on the 1st of February i called him and told him my problem he said he will get back to me.he didn't i had to come to the store only to find he is om leave no one wanted to assit me.i asked for a refund they refused.they talled me i should talk to the person i bought this product from.i even asked desmond to assit he looks not interested so please help