I once bought a horse complete with bill of sale, registration papers, and an honest handshake. It was a done deal. Several months later, the person that had sold the horse to the person that I bought her from started bothering me. She wanted me to sell her the horse at the price that she had sold it for ($700). When she sold the horse, it had been starved out. The guy fattened the horse up and I paid $1200 for her, which was a fair deal for this particular horse.
It got to be quite a pain. She stalked, harassed, and even threatened to steal the horse. Then she suddenly lost interest. It was a major hassle. I hope that this person also loses interest.