Gamecenter nickname problem !! Help !

I created account in game center and i used this account about 1 year , then i in one day , when i opened my iPad , i got massage to create new nickname in game center , my old nickname was Tayfour-1997 , and now Tayfour-1997k , i didn't know what happened !! All my achievements and all my friends deleted ! Plz guys , how can i restore my old nickname Tayfour-1997 ??! I played clash of clans and my level was 71 !!!!! Please heeeeeeeeeeelp !!!!!!