Riot uses a tier system for punishments, typically two escalating chat bans > 14 day temporary ban > permanent ban. Riot will skip the first 3 tiers in the most severe cases.
Having received the third tier punishment already, that indicates that coming off your chat restrictions that your behavior has not changed and your account keeps getting reported by other players.
When your 14 day ban is lifted, you'll need to go 3 complete months exhibiting good behavior in order to deescalate your account one tier of punishments. So if you get reported anytime in the 3 months following your 14 day temp ban, your account will be permanently banned. If you manage to go 3 months without being toxic, then get reported a bunch, you'll go back to the 14 day ban.
You clicked "I agree" to Riots Terms of Service, so the choice is yours:
- follow their rule set
- continue to do it your way and get permanently banned
http://static2.gamespot.com/uploads/scale_super/1551/15516851/2941774-lfs23.png