I wasted 100 nuggets because the store shows that you spend DP to
get nuggets. Now, that I've wasted 100 of my earned nuggets, I
can't get anyone to respond for a refund; I imagine people only
make this mistake once, but how hard would it be to switch DP and
nuggets?
There wouldn't be a refund, no. The page does say "You can buy
additional Dream Points with your Nuggets in this section.", so
it's clear that you're spending nuggets to buy DP, not the other
way around.