Sorry to hear about that. Alamo are generally very good and only allocate cars based on actual availabilty. Perhaps (as happened last year) some of the fleet was stuck in the North of the USA due to snow, as they move fleet around to meet the Christmas demand in Orlando.

Alamo / Enterprise / National are all the same company, so they often do allocate cars from one of the other fleets, and that is fine if the car is OK. Obviously in your cars they were struggling so didn't give you a very good alternative. If any car is allocated that you are not happy with (in terms of safety or wrong car group) you are at liberty to refuse it.