Koons Tysons Chevy GMC

I used to like Koons, but then I bought a 2005 Cobalt from them and the radio went on the fritz 9 days later and they refused to fix it at no cost to me! 2 days over the return period and they won't fix it. That shows poor customer service. I don't think that I'll ever buy a car from them again. I bought the car at Koon's Tyson's GM. The used car manager told me he could do nothing for me, but he hoped this didn't leave "a bad taste in my mouth", of course, it did. I mean, a couple hundred dollar repair over the $8,000 dollars I spent? Shame on you Koon's.