Product code has already been used

i am going back to the old original Sims 1 version. i bought 2 games each of this Sims 3 starter pack, now, because of origin, i can not use one and my son use the other!

the codes are already used! duh! i bought them so yes, i have used them! but, now i can't even use my own game on my new computer! or vise versa, all because the code is used! i spent a lot of time and money on these games and it upsets me i can't use them because og this origin. EA, you screwed up in my book!

so, going back to old school Sims, no origin log in register *! why can't i fix this issue?