In this case, you need to fill out Gmail recovery from prove your account ownership:
Click the link given here:
Choose I don't know Password. Type in your Email Address. Click
Enter the last password ***** remember
Check if it provide you options to reset your password.
Else, please click "I don't know" under Enter the last password ***** remember.
And then click "I can't access my phone".
And provide them as much information you can.
Be sure to fill out the form completely by providing your best guess to all the questions.
Provide you alternate email address as contact email address. Gmail team will get back to you on this email address.
If you still have other queries regarding this, please reply back to me the box given below.
And if you can take a second to rate my service(-OK or more -by clicking stars at the top of the page and choose submit), to credit me for my time, work and efforts, that would be greatly appreciated. Thank you.