Y did I get ban

The enforcement team does not use the forums. You would need to check the enforcement site for information about your suspension and to see about submitting a case review. https://support.xbox.com/en-US/help/family-online-safety/enforcement/how-to-submit-a-case-review

Keep in mind that LFG posts are only for looking for others to play a game with. They should essentially be "I'm looking for x amount of people to play this game with". Anything other than that will typically result in a suspension.

You will need to post here to find out -
forums.xbox.com/.../41.aspx

To check if your account has any active suspensions, you can log on to
http://enforcement.xbox.com and review your Enforcement history (click the orange hammer).

Game developers have the ability to build game-specific security into their titles and enforce their community policies independent of the greater Xbox Live system. This is often true for games that feature extensive player-created content or have robust
and active online communities. Since every game is different, the method by which you are notified of a game ban varies by developer.

Game-specific bans fall outside the scope of Xbox Live Policy & Enforcement, and XBLPET and Xbox Support cannot provide insight into game-specific enforcement actions. For specific information about a game ban, please contact the appropriate developer or
publisher.

How would i go about sending them a email or email contacting the developer or publisher