Unfortunately I can't help with the stuffing issue. I will say that repairing headphone cords is nearly impossible without just buying a new unit. It's a major fail point for most headphones and why professional In Ear Monitors (IEMs) all come with detachable/replaceable cords. Sucks to have your $200 headphones die because of a $0.10 cord, but that's exactly what happens
I recently received my second pair of Beats Solo 2 headphones as a gift. I really enjoyed the sound quality of my last pair. However, I did have a couple of issues with my last pair that I expect to have again. The first one was an easy fix. Namely, the auxiliary cord had a bad connection after just a few short months. It wasn’t hard to find a replacement. The other problem wasn’t as easy to deal with. After a few more months, the coating around the ear muff part of the headphone started to detach, exposing the stuffing. I really don’t want to have that happen again, so I’m seeking advice on how to prevent it. Also, I would really like to restore my first pair if there exists a simple way to DIY or even an inexpensive way to hire a professional.