Take it back to where you got it, and before they do anything with it - show them what it does for you. That way, they see what you are doing and can go from there. Take fabric and the thread you are currently trying to use with it.
I have a friend who was having issues with a different machine and they repair person just sat down by it and went, Oh here's the problem. She took it home and it did the same thing. So, make sure that you show them what is going on.
I have 3 Janomes and love them. One I have had for about 20 years and have had no problems with it.