I really think that you need to take the machine, some fabric and thread to the dealer. Call and see what might be a good time so that they can spend some time with you. If you end up having to leave it for repair, make sure that when you go to pick it up you take fabric, thread with you and don't leave the shop without sewing on it - for a while not just one seam. That way if it is something in the threading or user error they can help you and if not they can send it back to the repair person.