I think the easiest way to do it would be to notch the post so the chain doesn't slip. It will bind up tight. I had a similar situation where I had to remove chain link fence posts. I used a floor jack and sure enough it worked. I didn't have a hi-lift jack at the time. I do now thanks to a friend that didn't need 3 of them. I recently replaced 3 wooden posts at a customers house that were rotted just as you mentioned. Unfortunately all of them were rotted off and broken so I had to dig, dig ,dig to get the concrete ball out.