I'm assuming Fluido is your consultant? Or is that a tool?
So you have a smart list for the invitation that attempted to exclude Competitors and Unsubscribed?
Your Unsubscribed people should be fine because Marketo always blocked people with Unsubscribed=True. Can you pull a Smart List that says "Was Sent Email IS "X" AND Unsubscribed=True? to see if anyone pops up?
Your competitors are based on various filters, so that's hard to troubleshoot from here.
If you aren't syncing between SFDC and Marketo, that's a problem Fluido or Marketo Support should check on. Did you receive any Notifications? Can your Marketo User see the right fields?
If you aren't getting what you need from Fluido, try asking Marketo Support EMEA for some help.
I agree with Josh, unsubscribed leads would be counted as blocked.
The suggested smart list is a good resource to start identifying who actually received the email.
What is the program/event name?