Does the account have a name like "userXXXXX"? If so, fear not, that's a user name we generate for you by default if you didn't provide one. Most likely you've signed up with your email in the past and don't remember. Try to log in, and if you can't remember your password reset it: https://www.hackster.io/users/password/new
If you still think your account got pirated, then email us at firstname.lastname@example.org and we'll look into it.