NEVER ignore a demand to contact. That could screw you in a sourt soooooo bad! Make sure you call them if possible and tape the conversation.
The stars are making a move and celeb sites are the target. Recently the guy using different takes on the Beatles names was ordered to turn over the sites to the Beatles. And he was just using them to redirect to a mainstream commercial site.
If you comply with their wishes they'll leave you alone most likely but to ignore a possible real legal notice can really be bad for your sunlight. The sunlight could end up with stripes in it from bars. lol Don't get worried about it but do make contact. That would show that you are trying to work with them to a judge if one ever gets involved.
