Accidently redeeming a code for a game i already have.

Hi, i recently bought a game of G2A.com thinking it was premium for BF4, however i redeemed it and now i have 2 copies of the game, theres nothing wrong with the first copie i have and i wanted to know if i can just give the second one to a friend or something. Its my mistake in the frst place, but i dont understand why origin lets me have 2 of the same game in my library at the one time. Any help given would be appreciated, and yeh i know... i dun goofed...