Ban Problem

Dear Riot I got permanently banned and I do not understand why. I know I have done wrong by leaving games for reasons out of my control. I also know that I should not have taken the risk of being forced to leave and should rather have played in times that I know I would not be disturbed. I know it is fair to ban someone for being toxic or preventing other players from having a good game experience in any other way, but I have been banned without any previous temporary warning bans. I believe that this might be fair if it were someone cheating or disrespecting other players. I have not used any program to cheat and I always try to keep my chat clean. Please take this message in to consideration for I have spent a fair amount of money on this account.