I just finished a couple days of twisting, prying, pulling, cutting, sawing, splintering, and swearing to remove a carbon fiber seat post from an aluminum frame. Not sure if this will help the OP but here is how it went for me using some of the ideas from this thread.

I wanted to remove the post so I could ship the bike. The post would not move and I ended up putting the seat post in a vise and the seat post cracked.

I took a saws all and cut off an inch from the top of the seat tube. I then cut 5 or 6 grooves into the length of the seat post and took a pair of vise grips and compress the seat post to pull it away from the seat tube. The outer layer of the seat post didn't give but the inside layers broke away. I took a small flat blade screwdriver and a hammer and started separating the seat post from the seat tube. I used a longer screwdriver as a I made more room to work. I was also using amonia to dissolve the aluminum oxidation.

I kept using needle nose pliers to pull out anything I could get the pliers on.

Eventually, I had cut and pried most of the seat post out and the remaining six inches or so fell down into the seat tube. This part would not fall out of the frame if I held the frame upside down. I fashioned a hook out of a hanger and tried pulling it out. The hanger was not strong enough and kept straightening out. My theory on the seat post is that is absorbed moisture/amonia and was swollen so it would not come out.

The new seat post would not even slide into the tube so I took a brake hone (available at an auto parts store) and cleaned out oxidation in the tube until the new seat post slid easily into the seat tube.

I bought a steel rod (not sure of the diameter) at Home Depot and fashioned a small hook. I hooked it under the seat post, clamped vise grips to the steel rod, and tapped on the steel rod until I got remaining seat post close enough to re-commence the prying, cutting, and pulling with pliers. I kept whittling on the seat post until it finally popped out. There might have been all of three inches left of the seat post.

The new seat post went in with Fiber Grip which I hope prevents it from seizing again.

Do you mean seatpost, or did you really chop up the frame?

That is rather vague. Sorry about that. I cut the seat post off an inch above the top of the seat tube.

I think at one point I contemplated taking the saw to the bike and pitching it into the aluminum recycling bin. I had very harsh feelings towards that seatpost.

You didn't try the heat method huh?