My device is not accepting the real email to activate my ipad?

i have a real problem now, my ipad 4 is fully working when suddenly it came out to my mind to update it into newest version of ios 9.0.2 via computer.. when i did that.. my ipad4 restored and it went to dfw mode or something and after that.. when my ipad 4 is done updating my account id as far as me is concern i know my password and my account was used to enable my ipad in the first place.. then now even i tried multiple times entering my icloud or apple id , it appears to be the email you entered is not available to unlock the device.. somebody? i need to use my ipad now coz im having a hard time using my pc!