forget apple idi & mail address

If your phone is on the activation screen then does it not show the first letter of your iCloud account and the provider name - unless you can remember or find your full id then you won't be able to reactivate the phone.

If you can't remember your account id then do you have any of its downloads in your computer's iTunes library : Recovering a forgotten iTunes Store account name ?

If not then you could see if you can fid it via http://appleid.apple.com : Apple ID: How to find your Apple ID.

If you can find the id then try getting its password reset via http://iforgot.apple.com

If you can't get the password reset via that site then try contacting Support in your country to get it reset : http://support.apple.com/kb/HT5699

If your country isn't on that page then try this form and explain and see what they reply with : https://ssl.apple.com/emea/support/itunes/contact.html