My Main account got hacked

Hello there my real account got hacked 2 times dont know how the hacker hacked my account and changed email, password he got no way to access my Email associated with league account i made a new password with new ways to more secure i ran antivirus on pc and malwarebyetes too and my pc is clear even though the hacker HACKED MY EMAIL AGAAIN he contacted me and knew my facebook account and blackmailin me if i dont send money he will hace the account forever btw:i sent 2 recovery tickets to riot with information of my acc such as first purchase first champ which the fuckin hacker dont know PLS HELP