Real Racing 3 won't let me sign in to my account ("Guest" problem).

lately i could only compete as a "GUEST".  
i try to sign in using google play\gaming hub and it goes to a screen where it opts me to put my email adress and says that "this account will be add to your device" (image "1")

the thing is- that email (gamil) account is ALREADY ON THE DEVICE.

so when i type my email and click "next", it says "This account already exists on your device" (image "2")

and i cant put my password, so basically all my progress (long long progress) in the game is gone!!!!!!

how do i restore it? i cleared cache, i cleared data, i un-installed and re-installed.

what the.....****** is this!? 

i add 2 pictures so you can see what i mean.