my account has been overwritten

My old account has been overwritten by a new account.(FC MOBILE)

My old account is linked by facebook, when i wanted to login to another device, there pop out to chose an account i acidently click wrong and my accouny overwritten by new account. I wanted to recover it back my old account. I have played for 2 year , if my account be overwritten every progress have been "deleted" , i need to restart it again.Pls help me.