I too have a Janome 6600 - love it. Have never had 1 problem with her and she is used a lot! Piecing, Quilting, mending, jeans, sheer and I love love love the Janome machine needles - the right needle for the right job.
But I agree with others who have suggested getting in touch with Singer. By no means should you have had that trouble. Perhaps Singer would like to know how much we discuss machines on this very large web site. Keep us informed on your interaction with Singer. Machines are bought and sold every day.
Good luck -