How should I handle this?

["Gorman, Ken (PA62)" <Ken.Gorman@iac.honeywell.com>]

Listers:

Placed my 96 Audi A6 for sale privately.  Agreed to a price with a buyer.
My bank won't give up the title until they get funds to cover the remaining
balance on the loan.  Buyer's bank won't give funds until they get a title.
So...I place a call to a local Audi dealer for advice.  

The Audi dealer offers to handle the transaction.  It works like this.  I
sell them the car.  They re-sell the car to my buyer.  They charge $150
service fee for the paperwork transaction.  The dealer also convinces the
buyer to arrange financing through them.  Everyone's happy.  Right?  Not
exactly.  The dealer makes an accounting error in determining who is owed
what money.  Without getting into the particulars, I am charged the $150
service fee twice.  I contacted the dealer who admitted their mistake,
however, not only did they underpay me $150 they overpaid the buyer of my
vehicle $150.  The dealer is unwilling to send me a check for $150 until
they get the money that was overpaid back from the original buyer.  The
original buyer is not returning the dealer's phone calls.  I have tried to
contact the original buyer, and am having the same problem. 

I paid the Audi dealer for a service.  They made the mistake, yet I am made
to pay for it.  I feel that it shouldn't be my responsibility to track down
the buyer to get my $150 although I have tried to do just that.  I have sent
several letters and left several messages for the buyer.  I have contacted
the Audi dealer 3 times - all to no avail.  At this point, it is not
necessarily the money, but the principle.  What should I do at this point?

The ironic part is is that now I'm in the market for a new Audi and won't
even consider going to this dealer.  The dealer is losing a new car sale
because of poor customer service.

Any advice from the list would be appreciated.

Ken Gorman