okay honestly you can get it back by talking to riot support. literally just claim you were not in ownership of the account at the time of the flame etc. (claim you were hacked) or something like you sold a computer with your private information like league details in it somewhere. it sounds stupid enough but it has seriously worked for me and friends in the past. ofcourse if you have TONS of flaming offenses from scattered dates it wont work, wish you the best of luck