It "didn't work" because they did not listen. Dealers NEVER listen.

Your car was fine, you took it to them to get the stuck key fixed and they $*%**$# it up!
Now they expect YOU to pay for their screw up? 180 is right, time to get Chrysler involved. This is B.S.

I do NOT see how they could turn such a simple fix into a nightmare - but we have seen this time and time again on this board.
I keep saying it - DO NOT TAKE THESE CARS TO A CHRYSLER DEALER, if you can't fix it yourself (and many of us can't) then take it to a local, independant shop that works on Mercedes products. This has worked well for me on two occasions.

I know it's too late for you this time, but maybe if I keep saying it, it'll save SOMEONE out there from the same nightmare.