An epica battle

I BOUGHT an ex-demo Holden Epica CDX in December last year. Since then I have had some problems with it and was wondering if anyone else has had the same experience. The front interior door handles needed to be replaced after the plastic came away, causing cuts to the hands when using them. The brakes have ``failed'' half a dozen times and the dealership is unable to find any reason for this to happen. When they fail, the pedal goes rock hard and I am unable to brake straight away, taking a second or two to come to a complete stop. This is accompanied by a horrendous grating-type noise. One positive is this only seems to happen at low speeds. The anti-skid and traction control warning lamps come on and stay on for no reason. The service department told me this could mean a fault with the anti-skid and traction control, or could be a sensor issue, but either way required a service to fix the problem with the computer. Before I could book the car in they went off -- something I was told wouldn't happen, as it needed to be hooked up to their computer to turn them off. It is getting very frustrating. Is anyone else having the same problems?