8015D003 error message

I haven't used my xbox live account in a few months since I have been studying at uni, but I come back to find an 8015D003 error message upon entering my password for my email.

So I go onto the Microsoft site and enter the details and it comes up with a message saying that someone else maybe using my account. After checking with a friend on my friends list whom I know in real life I can say that my account hasn't been signed into
on xbox live, showing an 'offline' next to my name.

The email that I linked to my xbox live account when I created it is very old and I don't use it any more, its only use is for this now, so I attempt to 'recover' my account, After entering the information that I can, I get an email saying I haven't provided
enough, yet I provided everything except the recently send emails and any other folders created, because I haven't used it in years; I don't know these. (I even had the prepaid last 5 digits because of a photo on my phone).

So my question is: what can I do from here to recover my account?

I wish to change my email linked to my gamertag now to one I actually use and maintain, will the parental email on my xbox help? Or is there another way to get my account back, any extra information I can provide to prove I am the owner. I just don't understand
why this has happened, what was the cause of my email suddenly becoming corrupt or otherwise comprised after 4 years of no issues?

Any thoughts or answers would be greatly appreciated,

Thanks

p.s. this account I am using to post this question is not the email nor the gamertag in question, only something I created so that I may ask.

:)

 

microsoft account misshap

Try the steps in the article below

support.xbox.com/.../error-code-8015d003

 

signing into profile troubles

That error code suggests an issue with your account. Please try the steps linked below.

support.xbox.com/.../error-code-8015d003

 

Hello There DogmaticGnu6

This page HERE may help you to recover / remember your forgotten email address (Microsoft Account). You will need to fill
out the account recovery form here.

If the above page does not help you, then please contact support. After providing them with your gamer-tag, they will go through some security questions with you to prove that you own the account. Once they are satisfied that you have ownership, they will
release the email address tied to the gamer-tag and so on.

Go to the bottom of the page Support Resources > Contact us > Step 1: What type of issue are you having? > My account > OTHER POPULAR TOPICS > Need help getting access to Microsoft account > Step
3: Choose a contact method > CHAT WITH MICROSOFT SUPPORT. Explain the situation and they will be able to help. You can also
REQUEST A CALL FROM SUPPORT.
Good Luck DogmaticGnu6