CarMax Independence Boulevard

Purchased my vehicle from the Independence Blvd location in Charlotte, NC on Sept 6th. On September 13th this vehicle required roadside assistance to have it jumped. The mechanic just laughed at how loose the battery was in the car and said it was a three year old battery.The next day the car wouldn't start and couldn't be jumped. I've been told now by CarMax that I should just buy a new battery because the next appointment to have it looked at isn't until next week and if the new battery doesn't work I would need to pay to have it towed back to CarMax and I'd be refunded later. I had a great and pleasant sales experience buying the car but I can't imagine going back or recommending CarMax to anyone if they can't simply take care of towing a customers car back and fixing the situation after only purchasing the vehicle less than TWO weeks ago. The salesman who sold me the car won't return calls, texts emails from me also.