Hello my name is ***** ***** certified computer professional with over 10 years experience. I will be happy to help you.
This is a difficult situation for sure and unfortunately there is no easy way around it however this does not mean all hope is lost but it will take some time and patience. The first thing that you must understand is gmail is a free service and also they do not collect a lot of information about the user when the account is created. They leave account recovery up to the user by allowing the user to add a cell phone number to the account which you can use to get back in or an alternate email address as well.
My guess is that none of these were updated which has left you with the last resort option of filling out the questionnaire to prove it is your account.
Please understand, this is all done for the security of the account which is why it is so difficult, also because gmail is free they do not have a phone number you can just call and have someone help you.
All of the above said, I have helped many people in this situation so I am going to share all of my tips with you on the best ways to recover the account at this point.
Please read through these instructions at least once before you try so you understand.
Go to the following link to begin the recovery. https://accounts.google.com/RecoverAccount?fpOnly=1. Enter the account you need access to, type the characters in the distorted image, and click the link at the bottom of the following page to verify your identity and access the form. When it gets to the recovery options page click Verify your identity
Then you need to answer these questions (the questions may be a bit different but usually these are the standards),
When was the last time you were able to sign in to your Google Account? (take your best guess)
When did you create your Google Account? (take your best guess try and get at least the year correct)
Email addresses of up to five frequently emailed contacts (name as many as you can, do not guess)
Name of up to four labels or folders in your gmail account (name as many as you can and do not guess)
Select up to 4 other Google products you use with this account, and the approximate date you started using them. These could be things like youtube or google plus. If you are not sure leave blank.
What is most important is you do not guess. You need to provide as much correct info as you can. So if you do not know something skip it but try not to skip everything or they will not let you in.
Take time to fill out each section of the form to the best of your ability. It was designed to ensure that no one can gain access to your account except you.
If you fill out the recovery form and aren't successful on the first try, you can try again. Make sure to wait until you receive our reply before you submit another report.
Important: Try to provide as much information as possible on each attempt. Each submission is evaluated independently. So as you try going through the form and failing try and think what you may have taken a wild guess on and next time you try leave that answer out.
Remember you do not have to answer all these questions 100% correctly, you can skip some, but you need to at least provide enough correct information to prove it is yours. You may need to go through this a couple of times.
Fill in the information the best you can and try not to leave too much blank. Answer as many questions as possible, and make sure your answers are accurate.
If you fail 3 or 4 times in a row you may be shown an option to have a representative call you to help more. I have seen this happen but I am not sure exactly what triggers it but I have seen this option appear when helping others.
I truly hope this information helps you get back in the account. Please do me a favor and take a moment to rate my service and advice by clicking the stars above, 3 or more is very appreciated, we can still chat after rating if you need more help.
Please remember you are rating me personally and not your frustration with the situation or gmail's policies and procedures which I have no control over.