I had the same problem. You should have tried a twist approach too instead of just hammering it out. Im sure you did but just didn't record it. What I finally did to get mine free was using a 20" pipe (monkey) wrench and twisted that sucker out of there (the more twist force you put the harder it clamps). It totally marred up the post with teeth marks. I soaked and re soaked in PB blaster for 4 days before this successfully worked though. I actually twisted it so hard the seat clamp actually twisted off the seat post, so the post was ruined but the frame was fine. I also tried the hot/cold approach with no success. I also tried sledge hammering it further into the frame just to get it loose enough to pull out!
Luckily it was a 5 pound steel beast that could take the abuse.