i have changed a good bit of rear axle bearing and to any one who says it should just come right off there inexperienced. if the caliper, jam nut, collar and c clip are removed and the aluminum rotor hub will still not come off, the new holding force every one is forgetting is corrosion. corrosion especially likes to happen when aluminium is against steel. as it is in this situation.

soooooo since you already broke and ear off it, the hub is junk. i would put a deep score in it with a grinder and a cut off wheel then hit a wedge/chisel in that score to crack it the rest of the way. with that added clearance from the crack the collar could be free to come off. if no do the same 180 degrees from the first and remove the hub in 2 pieces.

for future reference aluminum expands 1.5 times faster then steel so heating the hub will give you extra clearance over the axle to remove the hub. if you have no access to a grinder you can still do this now. light tapping around the hub towards the center of the axle (in relation to the diameter of the axle) can also loosen corrosion.

hope this helps!