That's too bad about your 35's. I'm not sure what you can do to fix it. One guy I read about (here, maybe) used a lighter to soften the plastic and make the connection tighter between the clip and the phone. Not something I would even try, and it may not even be an appropriate fix in your case.
If I were you, I'd buy another pair. I'd also send the old ones back to KOSS for replacement under their lifetime warranty. Unfortunately, they will replace with the KSC-50, which is not as good, in my opinion (I know, I've had a damaged pair replaced by Koss with the 50's).