Doesn’t block blocked addresses

Hi!

I’m having issues with fake/spam users registering at my website. I am using your plugin and reCAPTCHA, I have included the emails in Block List and Blocked TLDs with and without wild cards (and made sure I check the To block usernames in this list, check this box-box), blocked all countries and signed up for all Web services, but I still receive fake’s from the blocked emails e.g. *.instambox.com.
It is also strange, perhaps a clue, that all users, fakes as well as my own admin accounts, show my domain (not-dedicated) IP-address as User IP.
Any idea why the block doesn’t seem to bite? Could it have something to do with the IP-address being the same as for my server? I have used the default to whitelist admin IP.. Is there a safe way to not use this function or other alternatives (e.g. getting a dedicated IP) if this truly is their entryway?
Anyone else had this issue?

Any tips would be very appreciated!
Best,
Robin