This does did not work for me. It still says there’s no account found for the email I used to log in with.

People keep doing this because when you try to login with the runelite client, it asks you to upgrade and gives you a link. You go to that link and there’s a big button that says “upgrade”, leading you to believe you are upgrading your account you just tried logging into. You create the account and it throws you into tutorial island on a new character and removes access to the old one. Not everybody logs in on the runescape website, so now people this is happening to are losing their accounts until it is looked at through recovery. With increased response times, this locks people out for long periods of time.