Looking for a german bondage story

[wurstdl]

I'm looking for a story, that I've read a few years ago on a german speaking swiss story site. I believe it was called "700 Meter unter dem Berg" or something like that. It had about 20 chapters and was about a girl getting kidnapped and put in an old bunker deep in a mountain. Sadly the site has been offline for a few years now and I don't know exactly what it was called, though I think it had a .ch domain. If there are some german speaking people on here, it'd be great, if somebody knew about the story or the site name.