I was removed from xbox ambassador program how can i join again ?

Typically if you're banned from the program it is permanent. However, if you were removed due to an enforcement action, and the enforcement team overturned their decision after you submitted a case review, you can contact Ambassador staff to be added back. You can email xboxambs @ microsoft.com (remove the spaces) to contact staff.

Social media pages of Xbox does advertise the Ambassador program now and again. Thats how i joined the program.

This time next year, providing the Ambassador requirements don't change, you should be able to re-apply to become an Ambassador for Xbox again.

Just to note, the 1 year requirement for joining the program only applies to joining for the 1st time. If you are removed from the program, you can not rejoin. Part of the requirement for remaining an Ambassador is that you cannot have an enforcement action
on your account.

Once you get any enforcement action against your account you will be removed from the Ambassadors program and wont be able to join again i believe.

I believe that the way it works now is that if you leave the ambassador program or get removed then you can not join again so there's nothing you can do.