I play a game on my iphone but it got stolen. I need my original itunes account in order to play again but i dont know it. Please help

Basically my header says it all. I play this game and in order to get my account back they want my original iTunes account back but i have no idea what it was. I have tried everything I think it could possibly be but to no avail. I really want my game account back because I invested a lot into it. please help me out guys. Thank you all so much.