Gamertag changed by xbox.. I payed $10 for it

You're allowed to change your Xbox gamertag once for free. If you're trying to change your gamertag for a second time, You'll have to pay for the gamertag change.

I changed my gamertag once when I created my Xbox account but then, I decided to change it again and I had to pay around $10 I believe.

You would have to go to http://enforcement.xbox.com for information on why it was changed and to see about submitting a case review. If the enforcement team overturns their decision,
you will be allowed to change it again. If not, you will have to pay if you want to change it again.

you have to pay 10 € xbox to change your gamertag

But i cant help xbox glitched i only checked availability and it changed i never wanted to change it in the first place now im forced to pay $10 for a name change

Xbox didn't glitch. Awhile ago when xbox gave the opportunity for same gamertags with a number code after it, everyone had a free gamertag change. Unfourantaly if you want to change it back, you are going to have to pay $10 to change it back.

The only way that you would not have to pay the 10 dollars is if when you signed up for the xbox profile it automatically generated the gamertag for you.

If you go to pick your own gamertag at the beginning or if the gamertag you picked at the beginning was in some form a violation of the code of conduct and the enforcement team did a forced gamertag change then you would have to pay the 10 dollars to change
your gamertag.