Not only leaves can get you banned - verbal harassment, flaming, intentional disruption of gameplay etc. can be reported after a match. I guess you got a lot of reports.

If s.o flames me i give him/her answer. But i behave others good.

You won't find answers here. Read the mail you received from Riot.

You got served!!1

Well let me explain something about reports and ban.

1. You play solo que normal or ranked you will get banned for sure. Why? Coz there are always some random noobs who will report you for no valid reason. Yes they will feed and sure thats your fault. Yes they will flame you and in the end they will report you for flaming.

2. RIOT will decide one day to ban all ppl who has for example 70 reports. They will not check why did you get reported or who reported you. They don't have enough ppl or time for that. And yes they will just do auto ban like that. So in fact RIOT is supporting false reporters and stupid kids who does that.

3. What to do? Find better game to play or dont play solo coz I repet you play solo a lot you will get banned. It also does not matter if youre reported 40 times in 2000 games which will make you worse then some real flamer idiot who was reported 30 times in 35 games coz I tell you they dont check anything just do AUTOBAN DAY.

GL RIOT I see youre working hard to destroy all the fun to honest ppl who play this game and yes gj for autobans that will do the trick ! -.-

Would just like to add that when bans are done, your money spent and elo gained will not affect the outcome, everyone is equal in that respect.