So I have 21 red presents, and I was told to press "Use" to change them and nothing happens. I've tried numerous times.

http://prntscr.com/5f162w
http://prntscr.com/5f16lz
http://prntscr.com/5f17k3

it's because you're using them in bootcamp. i'd assume they aren't usable in bootcamp to prevent blocking of obstacles.
switch to a regular room and use them instead.

It's also happening to me but it's not the rooms