Based on what I know about Ticketmaster and their protective attitude of their tm....I would not even bother fighting it.
( I have a friend who had a name tied to them ( that did VERY well for him ) in the past and TicketMaster made it very clear that they wanted it back .... and got it )
So unless you feel very confident, can afford a good attorney and are willing to spend alot of money ... let it go. Its not worth the aggravation.
imho