Avis Rent-A-Car (Portland Airport) huge charges for breaking hidden rules Portland, Oregon

I rented a car from Avis as part of a Travelocity package.  I picked up the car at the Portland, OR airport on 6/1/11 and returned it on 6/8/11.  Two weeks later, I received a letter stating that Avis was going to charge my credit card $250 for "excessive soilage" to the rental vehicle.  This struck me as outrageous since the car was fine when I returned it.  The garage attendant had checked and okayed it. 
 
I repeatedly called the telephone number given on the letter, but could not reach anyone; I only got a labyrinth of voice mail boxes.  No one returned the many messages I left.  I then e-mailed the representative whose name appeared on the letter, Shelley Stewart.  On July 4th, she replied: "Vehicle was rented to you as a smoke free car.  The $250.00 is the detail fee to restore the vehicle back to a smoke free car." 
 
I did not know that the vehicle was supposed to be smoke-free, and I do not see how I could have known.  That information was not provided on the Travelocity site.  I read all of the fine print about the Avis rental that is provided on the Travelocity site, and there is no mention of a smoke-free policy.  There was no sign or advertisement announcing a smoke free policy at the Avis kiosk in the Portland airport.  This information was not provided to me by the agents at the counter.  No such statement appears in any of the materials that I signed.  I still have the copy of the contract I signed, and the information does not appear there.  There was no "no smoking" sign, sticker, placard or notice anywhere inside the car.  I know this because I checked carefully.  I have seen other rental cars from other rental companies that do have a no smoking sticker in the window, but the car I rented did not have any such sticker. 
 
It is not reasonable, or legal, to charge a customer for violating a policy without informing the customer that such a policy exists.  In addition, the amount of the fee is outrageously high.  Hotels, by comparison, charge $50-100 for smoking in a non-smoking room. They also carefully inform the customer that it is a non-smoking room and that a penalty applies for violating the policy.
 
On July 5th, I wrote back to Shelley Stewart explaining my views.  I asked that she reverse the charge and that the company begin informing customers of its no-smoking rule.  At the end of the message, I wrote: If you are not able to take action on this matter, please provide me with the name and contact information of someone who has that power.  I have not heard anything further from Ms. Stewart or anyone at Avis.   I sincerely believe that this charge is unfair and unwarranted, perhaps even illegal.  Who knows what other scams for collecting "excessive soilage" fees Avis may be using?