I had something similar happen to me 2 days ago. Key fob and button above licence plate didn't work but button inside did. After I opened it via the button inside both other buttons worked fine
Here's the post about it.
http://northernvirginiamustangclub.com/forums/calendar.php?do=getinfo&e=115&day=2015-9-12&c=1
Looks like if you're not a club member you have to contact someone beforehand.