Junk MyBB IP issue

So I recently started using MyBB. At first I didn't know how nice it was considering the fact that it's free, but not the point. A random person registered an account, and it's requiring me to activate that account. However, every IP on the website is showing as the IP I was assigned by my web host. This could be a bit of an issue. Anyone else experiencing this who can possibly provide a fix? Thanks.