So a friend of mine bought this frame off some guy on craigslist. At the time the seat post was stable and wouldn't twist around, but I noticed that the seat clamp was installed at a slant, so I took it off and put it back on straight. When I put it on the correct way, the seat post was loose and would allow the seat to spin around in a circle.

My buddy contacted leader and they said that they didn't have any replacement seat posts because they were back ordered. I figure this means "sorry, we don't want to fix it right now."

Since it's seat tube isn't the standard round 27.2mm, I don't know where to find a replacement seat clamp. Does anyone know where I can get one or how I can fix it? I tried just sticking cardboard in the seat tube to wedge the post, but that didn't fix it for long. Ideas?