Will your extension secure enough so you can rotate the spark plug out? If the plug is loosened enough I would believe it should come out with the plug socket. The rubber boot in the plug socket is likely gumming up the works just enough to have mildly seized the plug socket to the plug. I would try a different assortment of extensions until one of them is just snug enough, and if that doesn't work I would use needle nose pliers to pick at the plug socket. Try lightly rotating in both directions, the opposite way, so you can also slightly undo any cross threading you may have done between the plug socket and the plug. Something will work. Keep trying.and I can't retrieve it from the spark plug well. I am out of ideas and need help. The extension won't lock on the socket firmly enough to extract it and I can't get the plug out.
Any ideas are greatly appreciated