Xbox name change

As long as your old gamertag hasnt been taken since you changed it you should be able to get it back by doing a name change

If you go to your profile then customise profile then click on your gamertag and enter your original name click check availability and you can then see if you can get your old gamertag back it might have a # with numbers though.

That's odd that it would say it was $5. Gamertag changes have always been $10. So you would have been charged the correct price. If you have any screenshots showing the $5 price, you may want to contact support to see if there is anything they can do,
but otherwise the only way to change your name back would be to purchase another gamertag change. They do not offer refunds on gamertag changes.

Hello @[Mookie]!

There could be multiple reasons why you're experiencing this issue, most likely the gametag is already taken and is currently in use by another user. However, I would suggest changing is online here: Change Xbox Gamertag | Xbox to see if it works. If not, please try using a different word or a different combination of words. Hope this helps!

Xbox gamertag FAQ | Xbox Support

I am surprised that you do not think the name "Ebola" is not offensive. There is no appeal that you make. Once changed it is final. There are no more Forced free name changes as people would just keep making bad names. No matter when you created the name
- Ebola is always a horrible world tragedy and very sensitive to people who have been affected by it. You should learn by your mistake and create a name that is E for everyone and within the guidelines.

You will need to pay the 10 dollars just like the rest of us.