First Broken cam & Frayed cable then broken string

When the Quad 400 is not broken it is fast and accurate. I bought in 2009. Shot deveral times, followed maintenance instructions, kept lubed and waxed. Loaded a bolt and shot,bolt went 10 feet, cams were dented and cable frayed. Sent back to Barnett, they rebuilt thhe whole bow assembly. Got it back and shot 5 times very successfully, loaded a sixth bolt and the string broke when the trigger was squeezed for the shot. I e-mailed Barnett. The first time I sent it back they charged me $70 bucks. Hopefully this is covered. Guess I am hunting with my old Martin Tiger Bow, I have killed several deer with it. Slow, but reliable.