i just restarted my 3ds and NOW it worked.

what the fringe. good things come to those who wait (and curse and threaten their 3ds with a trip in the blender), i guess.
i usually kick people off my friends list after the trade's done (with a few exceptions), so that couldn't have been the case. plus, switching it off and on again doesn't change the amount of friends on my list. this is so weird, i feel like i'm in the twilight zone
but now it's working and i'm happy. <3 would you like me to come over or do you want to visit?