If the same neighbor has called the police regarding your activities 20-25 times in a two year period, and the police have on each and every occasion determined that you were doing nothing wrong, I would think that the police department would have done something about your neighbors by now. Have you EVER had music playing (loud or otherwise) when the police arrived? Did you turn it down as soon as they arrived? Have the neighbors ever called the police regarding loud music when you were not playing music AT ALL? If the police found no reason to cite you for a violation, they probably told the neighbor that their only recourse against you is a civil suit for nuisance. I have to believe, however, that there is more to this story that you have left out. What caused your neighbor to focus on you? (Or do they call the police on all of the other neighbors too?) One thing you might do is contact the police department and ask for their call records and reports for every call to your home in the last 2 years. Then talk to someone at the police department and ask them to talk to your neighbor.