CarMax Sold Faulty Vehicle IHouston, Texas

I purchased a 2010 Toyota Tundra Limited from the North Houston Carmax, that apparently had an aftermarket alarm, which malfunctioned within 3 months of buying the truck. I never thought about the alarm as the truck is basically new (4k miles) and the key chain / control functioned correctly. Once the alarm started going off, for no reason, while parked, while driving and couldnt be controlled by the key chain, I went to the Toyota dealer.

According to the Toyota dealer, the aftermarket alarm, which is mounted in plain view on the fender well was not installed correctly and was affecting the entire electrical system. I assumed that the brain trust that checks vehicles bought and sold by Carmax actually knew what they were doing but apparently I was wrong. For Carmax to buy a vehicle, look under the hood and not know that a non-factory alarm was installed makes you wonder what they check, the oil level?

My vehicle is covered under the original OEM warranty but what about the majority of the people that buy an as is car from Carmax? If it starts, has 4 wheels and the radio works, is that Carmax ready? 

To be fair, Carmax did agree to have my almost new truck towed to their facility sometime next week and their experts would remove the alarm and repair the electrical system that shorted out and fried the battery but they refused to provide a loaner or rental car so I will have a vehicle to drive in the meantime. They also refused to pay the dealer a mere $279 to fix it, they cant tow it and fix it for that. They've seen this truck and my business for the last time. 

Extremely poor customer service........Be careful!