Adding an RSVP Block to an email campaign is an Email Plus feature available in our 3GE templates. Your account has access to our Third-Generation Editor and is under our Email Plus billing plan. In fact, I took a peek at your account and can see you have tested a RSVP block in your most recent campaign. Please let us know if you have any further questions about your emails. We're always here to help!
Is there a way to get an email notification when people RSVP so we don't have to log into constant contact every day to check? Or is there a way to have the RSVP button link to a google calendar event?
Those are both feature requests we're currently tracking. I'm adding you to the list of people requesting them. If you think of anything else that could make our RSVP blocks (or anything else) better, please feel free to let us know!