https://support.riotgames.com/hc/en-us
If you file a ticket with our player support folks they can hopefully help you out.
Any chance you used a different email account for your original LoL account, then created a second account using the email you password reset with today? I've seen that happen before to people and similar resulting confusion. I don't think we ever reset accounts that have had a meaningful number of games played on them, let alone enough time spent to unlock all champs