Other Car Rental Programs/Partners (ie. Alamo, Enterprise, Sixt) - Avoid Alamo in SFB Orlando Sanford Airport

Just back from a trip to Florida. We'd reserved a mid-size car from Alamo. Only full-size available. We noted at the exit gate that it only had 1/4 tank of fuel. We didn't notice that the seats were splotchy with stains.
Upon returning the car, we asked to see the manager who defensively told us that we clearly picked out a car that hadn't been washed/detailed from its earlier rental. HUH? It was in the line-up of cars to be rented, not in the "Return Cars Here" line. Then he said that it was a "choice Alamo" rental, meaning that we could pick out a car we liked and we shouldn't have picked out a car with stains. Lordy, it was midnight and a poorly-lit lot, and we're supposed to be able to see seat stains in the dark?
OK, I really needed to vent. Any tips on the best way to deal with Alamo after the fact?

Lorna

E-mail Alamo corporate customer service. They usually respond pretty quickly to questions and complaints. For all the companies, airport rental cars are supposed to have full tanks. It's only neighborhood branches, since they do pick up service, that are allowed to rent with less.