I had a similar kind of experience a few weeks ago, also in Isaan (no debt involved though). A woman (whom I had never seen before, she spoke some English) arrived at my gate with a policeman, claiming that my dogs damaged her sister's car. And that she had pictures of my dogs, being on her sister's property. Sister's house is two properties over, but she felt she had to accuse the me first. I just laughed and told her that it would be physically impossible for my dogs to damage anyone's property in any way as they were always INSIDE my property (day and night). She of course did not believe me. I requested to see the pictures of my dogs, but funny enough, there were none. I called a Thai friend to explain the situation to her. Suddenly, she was no longer accusing me but saying that they were 'investigating'. And that next, they would check the property next to her sister's house (where there are many dogs, always outside the property). I also told her that there were many street dogs in our area and that my two neighbors had dogs too, which seemed to surprise her.
The moral of the story? Many people seem to try to make a quick and easy buck!