I once watched a pump guy start pulling on one that was stuck like that. He had his hoist under full tension when the pitless let go and the pipe shot up out of the casing about 15 feet before falling back down.
I would work hard to get that other piece of pipe on there. You can use a larger section of pipe 2-3 feet long as a slide hammer to pound it upward against the bottom of a tee on the pull handle a few times.
Since you put it in, you sound sure there is no cable release or anything. Make sure you have it tied off good in case something lets go.