Trying to register such a unique username is kind of like getting a digital "souvenir" (however, you should have kept such rare usernames blocked), though if you think about it, what is the use of early access? p.s. It's nice to see that you are quite active, but you probably need a lot of investment to scale. Try contacting Protonmail, they support this type of project ... and I also recommend that you post information about the project on producthunt (let me know if you need help).