Icloud

If you've forgotten your id have you tried : If you forgot your Apple ID - Apple Support ?

Or, and if you were the original purchaser of the phone (i.e. it wasn’t bought used ; if it was bought used and it's linked to the previous owner's account contact that person), you could try going to an Apple Store (make a Genius Bar appointment if you do) or try contacting iTunes Support online (https://www.apple.com/emea/support/itunes/contact.html) and see if they can remove the phone from the account - they are likely to want to see proof of ownership before they might help e.g. original receipt with the serial number on it

I can't, I'm just a fellow user.

To reset an iTunes account's password : http://iforgot.apple.com