Sew or not to sew

My machine is back home. I got it back last Tuesday and tried it out a bit at the sewing course. It seamed to be working sewing straight anyway. But I am a bit apprehensive in trying it out more. What if it still mucks up when FMQ? I hate the thought of yet again battling my dealer. Every time I have had it sent away it comes back with a note of user error... But what is it I am doing so differently from before I cant understand. Nothings really changed, still the same thread the same quilt, I've changed needles so many times in case it was them that made it all go pear shaped it is costing a fortune in needles! I will have a test drive in the weekend when I am off from work and have more time and patience to figure it out. Plus I have signed up for a Janome help group on yahoo and have been going through all their advice and hints to what I can try out. But obviously it isn't only me having trouble with this machine. Makes you wonder why they started selling the Horizon so quickly if there are all these kinks and problems with it....