The machine should be under warranty if bought new. I know I bought a Janome years ago and never liked it either. Couldn't get it to give me a good stitch and I have no clue what else I didn't like about it but I gave it away years later after keeping it in a closet for a number of years.
Most times Janome machines are great, my neighbor has them and that's the only machine she'll buy. As to the dealer not returning your emails, that's just plain lousy customer service. They must have known the machine was a dud and just wanted to get rid of it. I'd take it back to their store, plop it on their counter in front of everyone in the store and tell them,.....NOW ANSWER MY QUESTIONS since you won't answer my emails. They surely don't want others to know how they treated you. Sometimes you just have to get tough.
Hope you figure out the problem or maybe get a trade in machine. Might contact the company and see if they'll step in too.