I got banned for no reson

i just played a game of mythic shorty snipers and finished the game than lost connection and got banned I Evan have proof that I didn’t leave the game

By no reason you mean you forgot the quit you had the game before which triggered your ban one game later. System has a game delay between last quit and receiving ban.

Also so post ban related stuff at the top of this forum section in the future

All ban-related questions and discussion should be directed to the pinned official ban thread in the support forum:
https://www.halowaypoint.com/en-us/forums/e0d9938206f04a598ce84f2c8cadce02/topics/the-official-halo-5-why-was-i-banned-thread/19fa6556-e0b1-4248-b817-b3a99d0af5bf/posts