To crazyquilter. I have 3 Janome machines: one is a workhorse (computerized) that I have used for many years; one is a high speed straight stitch for my quilt frame and I've not used it much yet, so the jury is still out on that one; and the other is an 11000. The 11000 has been to the dealer's shop for computer upgrades and a couple of computer glitches. That's inconvenient because the machine is very heavy, but the adjustments and upgrades were done promptly while I waited and the shop is not very far from my home. Computer glitches aside, it sews and embroiders excellently. Any goof-ups have been operator errors.
Did you buy your 350E from an authorized dealer so that you have a valid 25-year warranty? According to the warranty, if you have a "lemon" they will replace it with a new machine (same model or as close as possible). If you purchased from a cooperative and helpful dealer, he/she should be helping you to do this. It doesn't seem as though you're getting any help or cooperation.