How can I remove a stuck coax cable from a conduit?

  In my newly-built house, an empty conduit was added into the foundation so that an antenna cable could later be pulled through. The conduit is around 9 meters long and has three 90-degree bends with a radius of around 30cm. The conduit is a corrugated PVC pipe similar to this image with 25mm diameter.

  Today, an attempt was made to pull a coax cable. I first pushed a nylon puller through (perhaps the wrong term, but it looks like this) from inside the house to outside (into the garage). That was a little difficult but I got it through. I then attached the coax on the puller; I used a wire to tie them together (I now know that I should have used tape).

  Then I pulled it back inside again, but after some meters it came undone, so the puller was completely removed from the conduit while the coax was only about halfway through. I was able to pull the coax some way back out again, but now it’s stuck about 3 meters inside the conduit. I measured this by feeding the puller into the conduit alongside the stuck coax until it wouldn’t go further. I removed the puller again.

  The coax seems to be stuck. I can’t push it in and I can’t pull it out. I don’t dare pull at it too hard because I know that the coax isn’t very strong and if it snaps off inside then I have no way to get to it.

  The conduit runs underneath the house, it lies in concrete under the flooring, so I can’t get to it without tearing half the kitchen apart, tearing up the parquet flooring, tearing up the underfloor heating, and so on. Absolutely not an option. There’s no spare conduit either; this is the only one and if I can’t use that then I have no idea how to get an antenna signal or sat cable into the house. That would be … very bad.

  Okay — I’ve just learned how not to pull coax. Can you now teach me how to get it unstuck?