Replying to Help me set my bindings!

almost everytime i land switch off bigger jumps if i dont land like perfect my ski pops off, and even if i do land good if i get just a little on my tails, or if i turn just a little bit i pop out. i guess thats because of the forward pressure? my shop is gay and they seriously dont know what switch is, so they set my bindings up pretty bad, i put my dins up to almost 12 and i only weigh 140, and they still pop out super easy. so how do i fix the forward pressure or whatever? if thats what it is.