Account Recovery

Ok, so, hypothetically, if I were to have an old account that I've lost access to, don't know what email it's attached to, or what number it uses, how could I get back that account? I have been having trouble signing into an account I know I made (it has my brand name and everything), but every time I try signing into it with just the username, I'm unable to. I tried the "forgot my password", but each time it says "too many tries" or something like that. I just need the account back as it's a part of my brand.