Replying to Bindings

Aight, so I got some Rossi Scratch 120 bindings and they're not working right. They keep releasing in dangerous situations even though I think the DIN is right, and I currently have a broken thumb because of it (one popped mid-air on a 3 and caused me to land real fucked up, as many here have probably experienced). They don't seem to click in well... they usually go up halfway and then I have to lift my foot up and shake it once or twice to get them to go up all the way... maybe that's normal for this binding but I've never seen it. My stats:

6'1
155 pounds
DIN 8
Salomon Thrusters in a 171, mounted 4cm back from chord
Nordica Supercharger Ignition boots
I ski them pretty hard, but they fall off even when I'm just goofing around and not fucking up