A good locksmith will have a tool to grab onto the sides and "break" the tumbler out. It will cost around 75-100 dollars. Alot better than screwing around with the dealer. Of course you will have to replace more than just the tumbler.
Ask an independant repair shop. I am sure that they have had to do this before and know which locksmiths have it.
1985 500SEL (260,000 miles) SOLD!
1974 280 SOLD!
1994 Volvo 850 Turbo Wagon (Yuppie Ice Sled)
"I know I have a Benz and they know it too." If you start bragging about it or shoving in people's face, you then become a Wally; especially to the girls.