Did you try contacting Sig? They have proven to be pretty comprehensive in backing/fixing their guns.
Hazcat had a Mosquito that jammed constantly. He got so fed up he was about to toss it until he decided to send it to Sig.
As I recall, it took two go arounds, but he got himself a sweet shooting .22 semi-auto for nothing but postage.
I've put a bunch of rounds through it, myself. I can tell you it is a real pleasure to shoot.
FWIW,
Crusader Rabbit