Wait, so you did not buy this pair of Dolphins from Penon but rather from some other store, it cracked, and now you need a help to replace it under warranty?
Either way, I know from reading other posts on Head-fi that Penon was able to help a number of people who didn't even buy headphones from them. That store is authorized dealer for so many different manufacturers, sometime they help other users to work through warranty process. Of course, nothing is guaranteed, but it worth a try instead of throwing these away - just pay for shipping to Penon if they agree to take care of it. Email them at:
penonaudio@hotmail.com and explain what happened. Their support is top notch. And honestly, Dolphins are worth fixing. I have so many headphones in my collection, and still use them on a daily basis.
Oh, and that pictures you quoted above is from my XDA review
I remember someone replied after my review with a marker around what they considered as a "weak" spot