over the last 20 plus years of wrenching on bikes
the majority of which in bike shops
the only freewheels i could not get off by
pretending to be a bus driver turning left
were when the two prong or sometimes four prong tool
damaged the prongs on the freewheel

if you are sure it is a conventional freewheel and not some weirdo hub
and the tool is not slipping
then you just need a little more elbow grease
i promise