Holy water seems to work, Just get a priest to come over one day. I mean generally ghosts are actually nice, and uncommonly you may run into a spirit who is troubled, but that's kind of rare, they're just lost and not sure what to do judging by what someone has told me and seeing videos and such online. You can just try asking them politely to leave her alone and that they're troubling her (or scaring her) whatever you prefer.
Edit: Also check your pm inbox, I sent you something today if you haven't checked it yet, it would be really helpful.