I got a random leave buster warning but in my last game I was participating and I won the game and that was the last game I played and now that I'm trying to play a new game I have to deal with leave buster. I was lagging the last game which might be a reason why I was afk but that's it
You must've not been participating too frequently during the match, Leaver Buster can't flag you otherwise. If your lag is that bad, just use this opportunity to figure out what was wrong so that you can fix it or try to avoid it in the future and not receive penalties if it's that bad.
If you need assistance with a connection (or any technical) issue, please post on the Help & Support board and the Rioters there will do what they can.
For more information on the Leaver Buster system and Low Priority Queues, read here; https://support.riotgames.com/hc/en-us/articles/201752714-LeaverBuster-FAQ
