I feel for you...we used to have a neighbor who's dog would bark all night while the neighbor was gone. I called the police but soon as the police would pull up, the dog would stop...then bark again when they left. You have to leave a notice on the door. Document everything with official looking notices. FIRST NOTICE: Make your first notice short and to the point-friendly cause they may not realize it bothers you. SECOND NOTICE: Make a youtube video documenting their barking dog with time as evidence and that they are breaking the law and further action will be taken with the youtube video as evidence to the police. Try to give them the benefit of the doubt because you don't want neighbors who will get offended and allow it to continue to be mean.