rsvp problems

When our guests search their name to RSVP, two copies of their name show up. Not on our guest list, or even on the search list when they initially search for their name, but when they actually are on the page to select I accept, pending, or decline. And this is a problem because unless you select I accept for both of the same name, they remain pending. So if Jane Doe selects I accept for the first copy of her name, but leaves the second copy as pending, it doesn't show her as attending. Help!