can't play C&C4 , changed email several times ,Key Code already in use

[guybarash]

hi, i own an (original) C&C4 game, 

i've played it several years ago , 

since then i've changed several Emails acounts, so i'm not sure which is the correct account

(not to mention password. 

now if i try to play with the given CD-KEY it says the CD-KEY is in use, by me i suppose... 

how can i play the game?