My League of Legends Account Hacked, Support Fails to Recover

I’ve been a long-time League of Legends player and logged into my account on August 16. After not playing for 10 days, I attempted to log in again on August 26, only to discover my account had been hacked. Despite having two-factor authentication on my Gmail, my Riot Games account's email and password were changed. Since the email was changed, I couldn’t reset the password myself, so I reached out to League of Legends support. I answered all their questions as accurately as possible, but they still claimed they couldn’t help. After consulting with knowledgeable players, I gathered even more proof that the account was mine and tried again, only to be told my information was still insufficient. After investing years in this game, I’m frustrated that my account is lost due to such poor support from Riot Games.