Results: What should I do about this cat?

Here's the situation. I live in a rural area in a duplex. There is another duplex behind me, and a neighbor beside me. My one neighbor (in the unit beside me) had a pet cat that they recently put outside to live. This animal comes over to my place and sprays on all of my outdoor furniture as well as my daughters outside toys. It also gets into my neighbors garage and destroys things. In the latest event, I was unloading groceries from my van, when I had turned around, this cat was inside my vehicle spraying all over the interior of my van and the remaining groceries. This is the only vehicle my family owns, and it had to be detailed (which was very costly and time consuming) because the smell is disgusting and extremely hard to remove. When I (or anyone else) tries to approach the neighbor, they kind of chuckle and say "we don't have a cat". I called my township and they told me they couldn't do anything because there isn't a by-law for cats. I then phoned the humane society, and they stated that they can not do anything because they can not prove it is their cat. Meanwhile the animal has a name and lived in their home for well over a year.