You need to know what gmail address you used in order to recover the data on it.
You can reset it entirely and use a new gmail address and the tablet will work but anything private to you on the tablet will not be there. You would have to download all of your apps again etc
If you have another Android phone or tablet we can find what gmail that is using. It might be the same one
i am confused here. how can the iphone and the tablet all be using the same email address but you dont know the password ***** it and cant change it?
what type of address is it ? normally the tablet would use a gmail address and the iphone would use an apple id. you can of course use gmail as an email in the iphone email app but you cant run the iphone off it the way you run an android off it.