I am a box seat season subscriber, and have made contributions in the past. It's a great orchestra and deserving of support. I made the mistake of giving them my unlisted number once and this is what I get for it. I won't give $ to an organization that makes these calls and abuses me (us) in this manner.
I had this same issue with Kimmel. And it's the first telemarketer that has gotten through to me in ages.
Here's what I have been doing to stop telemarketers. Get yourself a Google Voice (http://www.google.com/voice) account and phone number - it's free. Set up Google Voice to redirect all calls inbound to that new number to your mobile and/or home phones. Make sure you have the feature enabled that requires the caller to announce who they are. Use this number for anything public - tickets, online subscriptions, etc. I use it for everything except friends and family. Then, when someone calls, your phone shows their number and when you answer a message tells you who is calling. If they hang up on the announcement, go into Google Voice, find the recent call, and under "More" select "Block Caller". Voila! No more telemarketing calls!
Obviously this doesn't help your issue now, but between this and getting yourself on the National Do-Not-Call list, you can stop getting unwanted calls in the future.
It's a shame... I love going to the Kimmel. The arts are in serious needs of funding, but this is not the way to handle it.
It's a third party telemarketing company on contract from the Philly Orchestra. The supervisor's name is Reggie Howard. They apparently were calling from the Academy House. Ask for him by name. Tell him Peter says "hi."