Have you tried sending it to your number or another email address

It's known that gmail used your mobile number when you subscribed from the beginning.so enter your email address then click "forget my password ".then they send you how you want to retrieve your account.you select "send code as text message " option in which you can set a new password. Note that if the hacker could change the number this method couldn't be applicable.so if you were arranged another email address as retrival means in the "privacy" or "security" setting,you should try this email address instead of using your Mobile No.