I didn't think about the waterproof thing, that could be an issue if they've made it a pain to open. A while back I picked up a package of plastic tools that were more helpful than I expected. Profit brand, or something like that? They have some made for specific things, like an I Phone, but then some other general ones. There's a guitar pick shaped thing, other ones like mini screwdriver and crowbar shaped. And they all seem to be bright green. They've helped me get into some plastic things with less mangling than usual.
That sucks that you've got gear from a pricey brand but they won't respond to you. I understand you wouldn't want to destroy your nice stuff.