Mine got worn down too and I just went to a local ski shop that carried salomon (pretty much any ski shop) and asked them to get me new lugs which is what they're called. They ordered them for me and they came in like a week. You should bring your boots to the shop to make sure that the screws will come out and aren't stripped etc. first though.
But it was super easy, salomon is impossible to contact you pretty much have to do it through a ski shop.
kinda unrelated.... but there is a Salomon Shop (Like only sells salomon) in my town and the strap came off my SPKs. i went to them to ask if they could fix it and they couldnt, they told me to go to another store...How can they not fix their own products?
they're not in the business of "fixing" ski equipment, they are selling it. If you just needed a replacement part then that's odd they couldnt order it for you.. however ive had trouble getting in contact with salomon in the past. ive stopped supporting their products since.
OP just go to a shop that sells salomon the should be able to help you.
another idea if you want the straps that bad just buy some booster straps ive heard they work really well and i guess are pretty cheap, and you could also look at your local ski shop and they should be able to get you the replacement parts