You been booting the very edge of the tyre with your heel or a rubber mallet, trying to rock it off?
Put another wheel or something that'll absorb a potential fall from the jack, under the sill further up.
You're best persisting now, than at a roadside in the dark with no tools whilst needing to change to the spare!
When you get it off, put a bit copperslip on the hub face to prevent it happening next time!