Often members will contact us saying that they RSVP’d for an event, however Meetup.com did not add their name to the reservations for an event. If this happens to you, please keep the Meetup.com event confirmation.

It looks like:

This document is mailed directly to you from Meetup.com. If you did not receive a similar document, then there is a good chance, Meetup.com did not accept your reservation for a specific event. If that is the case, please revisit the event and try RSVPing again.