Can't log in after name change

I've been trying to submit a ticket on Riot's site but I'm in a pickle.

I was forced to change my login name like many others - I played a few games, logged off, and was unable to log in the next day. I tried recovering my account via email, but it's an email I haven't used in years (only created the email for account registration).

Google has locked me out of the email account saying it can't verify I'm the owner, even though I logged into the recovery email and retrieved a code they sent me.

So now I'm stuck - Riot will send a recovery link to the email I can't log into, and my new username is no longer working. Hope someone can help.