So what your asking is, your plug has broken off inside the headphone socket and how to get it out?
That's going to be hard, it also depends on how far in it is.
Unless you've got jewlers tweezers or very fine needle nose pliers I think youll need to dismantle your phone to get to the back of socket.
Sent from my GT-I9505 using xda app-developers app
Update: 17th november 2013
Samsung G S4 stock BMG4 + root
with cf-auto root + philz recovery.
HTC Desire HD
(Hboot 2.00.0029 AND S-OFF)
SVHD V 2.1.0
Retired HTC Legend