Origin won't let me play sims 4 after 48 hour trial version.

So basically what happened is I was planning to buy the sims 4 from Cex retailer but i wanted to try out the game first, so installed the 48 hour trial version.I played the trial version for a while and the next day I went to purchase a hard copy version of the game form Cex and installed it even though my trial version was still running (I didn't think it mattered or that it would affect my game play in any way). So I installed the game and it asked me for my serial code and I entered it and everything was working fine. But when the trial expired the next day, the game all of a sudden stopped working and Origin keeps telling me my trial has expired ? I tried uninstalling both Origin and the sims 4 and then reinstalling them but it didn't work. I did try to redeem the code but it says the code has already been used. I don't know what to do now and I've been trying to contact EA for days but they haven't gotten back to me. I'm getting really frustrated now because I feel like I've just wasted 50 Euro on a game that won't work.