I got a CD key for tomb kings DLC couple of years ago, played a few games, stopped playing and now its missing?

[jakobfx5j]

My friend 2 years ago bought me the tomb kings DLC. I installed it played a couple of games and i stopped playing for a while. now i want to start playing again and its no where to be found. I tried to re entering the code but it just says its owned by an another account... I checked my other accounts, but its not showing up there either. Is there a way to check DLC history or a way for me to get that DLC back?

[cSg|mc-Hotsauce]

When it tells you the key was used on another account, it should also give you the option to send an email to that account.