Blocked Mobile Phone. Gmail Address: [email protected]

My 13 year old son has managed to try and enter his password too many times and has blocked his mobile phone.  We have tried to reset to new password but says that his answers to questions arent enough information. He doesn't use gmail and has only used U Tube a couple of times.  He has only owned the phone since Dec 2011.  When we tried to reset password it asked "brothers name" which is Dylan.  Perhaps the lady in the mobile shop spelt it Dillon.  Please help me. We have the receipt of purchase for the phone, if that helps. Many thanks Sandy McQuiston