Sorry you have having trouble. I have the same machine and LOVE it. I know the bobbin cutter stops working when it needs cleaned. The dealer needs to show you how to do this. Your machine needs adjusted so the thread stops jumping out of the hook. When threading, be sure you go between the metal guide and the side wall on that first downstroke when threading. If you don't have a thin metal guide along that edge, have the dealer do a retrofit. Please take it back to the dealer, explain the problems and tell them you want it working correctly. It is a great machine and you should be tickled pink you have one...as soon as the dealer gets the bugs fixed.
Good luck.