I have had the same issues as the OP and in post #44 - both at the Houston Hobby Airport location. Regarding post #44, I have twice returned a car, been in a hurry and just headed to the bus, then never see a receipt only to have extra days added as well as the fuel charge. The first time they accused me of keeping the car until 4am on a Saturday even though I had flight receipts, dinner receipts, parking receipts, etc showing I had clearly returned to Dallas. Took several heated calls to get the charges removed.

Regarding the OP, I had a very similar occurrence a few weeks ago. I rented Luxury, was assigned a Ford Expedition (the longer version) with 20k miles on it. Protested that it was not luxury, so was offered a Ford Mustang. Again, declined that it fits the luxury category. Pointed to the BMW X5 and said thats closer to what I rented, and the Preferred manager just tells me to "take it".

Upon return I notice a $20/day SGU charge. Called Avis on the following Monday and they said I did a Select-n-Go upgrade. Explained the circumstances above and they rudely tell me there is nothing they will do, "you agreed to the upgrade".

Asked for a supervisor, put on endless hold and hung up, then received an email from the "supervisor". They say they reviewed the contract I "signed" and that they were not going to reverse the charge. It took me posting on their Twitter and Facebook to get it reversed - particularly demanding they produced the "signed" contract.

Avis (and the other companies) are purely despicable in their practices these days. They know people are not going to ride the bus back to the airport and go to another company (particularly if on a negotiated rate). Its simply a matter of picking the best of the worst if you ask me.