Gamer tag on my Xbox account is not mine

It is not the first time the gamer tag was changed. It was my account tried to change it to my sons with his gamer tag not mine.

You most likely used the wrong Microsoft Account to log in, this looks like a fresh Xbox account that has been tied to the Microsoft Account.

You have to find the email address that is linked to "dustdealer".

Make sure you have the correct info to log in.

It is also possible that you may have accidentally created a new gamertag overtop the existing one. You should create a new dummy email address for the account that you're posting with and then follow the instructions at the link below to move it to the
other tag freeing up your actual one.

support.xbox.com/.../switch-gamertag-to-different-microsoft-account

Based on your note, I assume you didn't have to do anything new or different to sign into your Xbox (e.g. your account name and password are the same, and only your gamertag is different.

It's possible that someone created a new Xbox account on your Xbox or recovered an existing Live account with the gamertag you show in your post. Hopefully you can just sign out and sign back in to your real account. Based on your post this is probably
not the case, but I wanted to mention it.

First question, does your new gamertag have your old gamer score, or is it a brand new account with zero gamerscore?

If it's just your old account with a new gamertag, you'll have your old gamerscore. Check to see if you still have whatever $$$ balance you expect on your account. It's likely that whomever did this spend $9.99 of your money for the gamertag change fee.
Honestly I don't think that's what happened, but you need to check.

More likely, someone got control of your account and changed the email that your old gamertag is associated to. In that case you signing in triggered Xbox to supply you a new Live account gamertag.

Either way, at this point you need to make sure you can answer security questions on your account -- secret question, name on account, last four of billing CC, phone, etc. The problem is that if someone got your account PW they could have changed all that,
or added something new, like an extra email so they get notification when you add or change security proofs or try to do a password reset. So just verify that your old security proofs are still valid. Go to accounts.live.com and view your security stuff.
If it's all there, then move on for now. Once you get this resolved you should come back and change things around, but that's later.

On the other hand if your security info is different or if you can't log in at all, you need to call Windows Live support. Not Xbox Live, but whomever now handles support for the Microsoft Account. Tell them your account was compromised and hopefully you
can validate by giving them other account details. Based on what you said, this isn't the case, and your existing login credentials still work.

Now it's time to call Xbox Support.

Phone is best. You can log into support.xbox.com and request a callback. That will tell you roughly how long the wait is.

Best to call soon, before the phone lines get flooded by people getting new consoles and games for Christmas.

Be prepared to validate who you are as mentioned before.

Be near your Xbox so you can tell support your Xbox ID# and Serial #.

Get a paper or write on a computer -- date and time, name of support agent, a few notes about the conversation as you see fit and most importantly the SR# for the call. If you call back or try to escalate, you'll need that number.

Once you validate who you are (i.e. the original "owner" of your old gamertag), tell them someone compromised your MS account and it looks like your gamertag was changed. Tell them you did not change your gamertag and that you want to make sure that no
funds were spent out of the account, either to change the gamertag or for any other purpose.

Your success hinges on your ability to prove who you are to the Xbox Support folks, and on (I hate to say) who at Xbox takes your call.

That said, since you have the console that the gamertag used to be on, they can look at transaction logs to see how and when your gamertag got taken. Not that they'll share that info with you though.

Be prepared to know that if someone took your gamertag and it's already in use by someone else, very likely you're out of luck. It sucks and it's not fair, but MS has no way of knowing if you changed it yourself and then changed your mind, or if whomever
has your old gamertag stole it from you.

It's tough but not impossible to do and mainly depends on what evidence Xbox Support can find to support your claim. And that often depends on your own tenacity and Xbox Support's willingness to pursue it. If you don't get satisfaction, ask the support
rep to escalate your SR. That puts it in the queue to a higher tier of the support system, and the agents there can investigate more broadly.

No matter how this resolves, go back and update your MS Account credentials. Create a new, random login (something like, *** Die E-Mail-Adresse wurde aus Datenschutzgründen entfernt. ***) and supply the strongest security information -- strong password, multiple security proofs, etc. Make sure to include
at least one trusted, valid phone number for texting and at least one email address different from your main one. Maybe even switch to the two factor authentication MS just put in, and set it up on the Xbox. Once everything is all set up, go buy a small
paper notebook and write all your stuff down, then hide the notebook away somewhere very safe, but where you won't forget where it is. This is not stuff to keep on a computer.

Good luck.

90% chance you used the wrong e-mail, 10% chance your account is broken. Contact phone or chat support and give them your old gamertag and this one and ask if they are on the same e-mail. If they are then they'll need to escalate your case, if they aren't
you'll need to get the correct e-mail.