Google take account privacy and security very seriously and will return account back only when you provide enough accurate information to prove that you are rightful owner. To recover your account please go to Account Recovery Form. Take some time with this form and give your best to provide the most accurate answers. That's the only way to prove that you are a rightful owner.
Account recovery tips:
Make sure to complete the form from a device you have regularly used in the past.
Make sure to complete the form from previously used physical location/IP address.
Answer as many questions as possible, and make sure that your answers are correct.
If you're unsure about some answer or specific dates, that's okay, give your best guess.
Do not attempt account recovery form multiple times in a row because you will get blocked.
You can reset the password ***** https://accounts.google.com/signin/recovery
If you do not have longer your phone number set on the account to recover it, you can click on "Try another way": you will get a proposal for
1) the last password,
2) phone number (new or old one),
3) security question,
4) Verification code by email
5) another email used in the past.
Remember to use a device and the browser you used in the past to access Gmail so will be easier to reset your password.