Need help with connection to Game Center

I need help. So far I´ve played for on default ACC (Player79…etc - dont ask me why I havent connect it to Game center) on my older iPad. Due to some hardware limitations, game started to crash very often. So I´ve got an idea to move to my iPhone. But here lies the problem. When I´ve connected to Game Center, it wiped out all my progress!! Is it any way, to connect my Game Center acc to my old default one? Thanks for any replies that may help, because I really dont want to play from scratch again.