Exorcise the demon quest bug

Hi so I've been trying to figure out how to get through the Exorcise the Demon quest for so long, I'm convinced it's bugged. I've reached the monestary and spoke to the sister, tried to use the scroll, didn't work, demon spoke to me and made me an offer. I asked what the offer was rather than saying "my will is strong blah blah blah", demon told me to kill the sister, but I declined to do it. Silly me went off and did some other stuff and saved so I don't have any previous saves to go back to. I know that declining the offer from the get-go is supposed to trigger the holy man stuff but there doesn't seem to be a way to get that to happen.
I've gone back to brother Resmus and he's all like "oh damn the demon tried to tempt you but you resisted?? That's wild man, but you still have to get rid of the demon. Come back when you do or shame upon you". I've spoken to everyone involved in this quest including the alchemist, father Anton, the dude at the monestary, and the sister again but there are no further prompts. I've tried talking to the holy man too but nothing.
Unless there's a skill check I'm not aware of?
I played the Quest to death when it originally released and I remember having the same issue back then. Is there any way I can finish this quest without restarting my whole game??
Pls help me
I've gone back to brother Resmus and he's all like "oh damn the demon tried to tempt you but you resisted?? That's wild man, but you still have to get rid of the demon. Come back when you do or shame upon you". I've spoken to everyone involved in this quest including the alchemist, father Anton, the dude at the monestary, and the sister again but there are no further prompts. I've tried talking to the holy man too but nothing.
Unless there's a skill check I'm not aware of?
I played the Quest to death when it originally released and I remember having the same issue back then. Is there any way I can finish this quest without restarting my whole game??
Pls help me