I just got a Wingostore 30-note with brass gears for Christmas a few days ago, I've been using it quite a bit, but now there's one wobbly gear that is making crunching sounds, slipping teeth, and getting stuck a lot. Is it defective? A lost cause? Should I see if I can return it for another? If they send me new gears instead, do you think that might help? Any advice would be nice, thanks!