I have 2 Janome and love them. I have the professional 6600 and use it all the time. Also have a small that I carry to quilt at church. Several of have the Janome Gem Silver or Gem Gold. I always use Aurifil thread on top and bottom.
Your dealer should make it happen. The dealer I use is wonderful. I am sure is irratating to have a machine that does not work.
Good Luck,
Dix