Unable to return a Pre-Owned game

On 15 March 2015 my wife bought a copy of Lords of the Fallen (PS4) which was a pre-owned title. When she came home I told her I already own the Digital copy for this game. BTGames don't want to refund the game for the total it was bought for. The came cost R599 and they are only willing to refund it for R120.<br> <br> i would like the full amount refunded or credited. I would imagine that according to the CPA this is ******* practice.<br> <br> Thanks<br> <br> AC