Hey there,
I can see how upsetting it is to lose access to an account you’ve had for a long time, especially when it’s connected to Xbox and personal info.
What’s happening here is that Microsoft’s automated recovery system needs enough matching details to verify ownership, and if the info you submit doesn’t line up closely with their records, the form gets declined automatically for security reasons.
The best next step is to fill out the form again from the same device, browser, and location you normally use, since that data helps confirm it’s you.
Be sure to include every detail you can remember, Xbox Gamertag, Skype contacts, and the approximate year you created the account.
If your email still shows semi-logged in on your computer or Xbox, could you tell me exactly what screen you see when it asks for your password?
That might give us another recovery path to try.
Regards, Aron