My GamerTag and account is changed!!

You added funds to your account, but did you actually complete the steps to change your gamertag? https://support.xbox.com/my-account/manage-gamertag-and-profile/change-xbox-live-gamertag

I just changed my gamertag and the EA account says I still have it linked to my old gamertag. I haven't changed my Microsoft account at all only my gamertag. I can't get it back since to change your gamertag it has to be under 12 characters and my old gamertag is 14 characters.

Hi there,

Yes, changing the gamertag again should be possible, als changing back to your previous Gamertag is possible, as long as your original Gamertag isn't already taken by somebody else.

Keep in mind each change will require a payment.

See this link for the steps on how to change the Gamertag:
https://support.xbox.com/my-account/manage-gamertag-and-profile/change-xbox-live-gamertag

This will help you convert the account to a Live Account:
support.xbox.com/.../offline-profile-to-gamertag

Just a warning the display name will change but you can change it to what you want for free:

support.xbox.com/.../change-xbox-live-gamertag

unfortunately you cannot combine accounts (if that's what you're asking about). you can attempt to delete that account and then change the gamertag on the account you currently use, but it is not guaranteed that you will be able to get it. you can find
out how to change your gamertag here:
https://support.xbox.com/en-US/my-account/manage-gamertag-and-profile/change-xbox-live-gamertag. hope this helps.