Now that the cover is out of the way, you will have to remove the "rivet / bar holder" (for a lack of a better word) that attach the earpiece holder to the headband.

Using a hammer and one of the attachment of the I fix it kit (ther is one that is very close in diameter), slowly hammer out the piece until it start sliding. You do not need much force here either.

Important! The bar has a direction! One of the side has a serrated end that lodge itself in the plastic and prevent it to move. Carefully observe which side it is (it is ever so slightly larger) and push from the other side. The resistance will tell you if you are doing it wrong.

After it has started to come out, use the snipe nose plier to pull it entirely. Be carefull to not hammer it out too much or you will damage your desk.

Once done, you should be able to slide out the last part of the broken hinge.