MoosMom, I would definitely make a report of her harassment to the police in your town....just to be on the safe side.
Also, I don't know what state you are in, but I know that in New York, cats don't "belong" to anyone, like dogs do. They are not licensed by the Dept. of Agriculture in NY like dogs. If the cat was roaming around outside with no id tags, she cannot claim it was her cat. As far as you knew it was a stray and you did the right thing by taking it to the Humane Society.