Mechanic Q: i have been trying to take off the fuel pump. We lifted up?

i have been trying to take off the fuel pump. We lifted up the bed so that we can get to it, but it seems to be stuck! I cant seem to move the outter rings, of the pump otself, it just wont budge......what do we do now?

Q: how do i get the fuel pump off of a 1996 GMC Sierra 4.3L??

the pupm seems to be stuck... it wont turn and neither will the outter rings? what now?