Gmail Account Not Retrun Account

my Gmail account has been comprimised yesterday They have changed the secondary email so I cannot just reset the password I have tried to fill out the form to regain control over your account but they declined to give me my account. I have filled it out as best as I can, but I cannot remember the dates that I set up (I have deleted the email that I got when I set up the account). I never use personal information with that email account, and I didn't really mind about it, but I have got accounts registered with other sites (VF, SF, EF etc.) on it. I have changed the emails and passwords on these sites, but I don't know if I have missed any websites. Is there any way that I can contact google (preferably by email) to sort out this?

I know people will try to say this to gain control over somebodies gmail account, but you can check my rep and posts, I am a truthful person. This is the email that Google sent me: Originally Posted by Google Thank you for your report. We've completed our investigation and cannot return your account at this time. We were unable to verify that you own this account based on the information you provided. If you can provide additional information to verify that you own this account, submit another report. Whether we can return access to this account depends on the strength and accuracy of your responses, so be sure to provide as much information as possible. If you're unsure about specific dates or information, provide your best guess.