If the problem is what I think it is--the end of the clamp bolt on the post is poking up and touching the bottom of the saddle??--it should be easy just to grind off the end of the bolt with a file, a Dremel, whatever tool you have around. Or cut it with a hacksaw, it it's WAY long.
If you can, threat a nut or the loose piece of the clamp onto it before you cut. Then when you take it off, it will straighten any damage your tool does to the threads.