I booked a mid-sized car at SLC via Hotwire (these were described as Ford 500, Pontiac G6, etc). The vendor turned out to be Alamo.

Today I picked up the car, only to discover that at Alamo, they consider a "mid-sized car" to be a Chevrolet Cobalt. I asked both, the person at the counter and in the parking lot, about this, and both said that Alamo now considers the Cobalt "mid-sized". No alternatives were available, short of paying for an upgrade.

Ordinarily, I would just shrug it off and just make a note to be careful not ot book "mid-size" and not to use Alamo again, but I'm renting for 10 days and I actually need the room (to transport four adults).

What, if anything, can I do to get this resolved? Am I wrong to feel that the offering here was grossly misrepresented and that they owe me a mid-sized vehicle?