The real estate lady we bought the house and shop from, sold a house by the nearby lake. "Owner financed."
The woman paid her monthly mortgage payments to the real estate lady for five years.
Then the owners of the property showed up.

Bunners

Well we own the property, and we had the house built ourselves. Then someone went onto one of the local neighborhood websites, and listed it for sale, with our address and everything, asking for $258,974. When my aunt left a comment saying that it was her sister's house, and that it wasn't for sale, the post suddenly disappeared.

Sounds like a scammer. I've heard stories about this kind of thing but I had never actually seen it happen or heard it happen to someone close to me... until now. It's a shame they took it down after your aunt left a comment. You could have reported them to the proper authorities. It's possible the person has done it before.

If you're bored and want a fun investigation, look at other listings by that seller and search up the addresses they have posted. It's possible you aren't the only person they listed the house of.