Complain to the police and keep complaining. Get your neighbors to complain (give them the contact numbers) and bring your local elected officials into it.

Dogs should only be off-leash in designated off-leash areas, preferably fenced, or in private yards. It's extremely rude otherwise, and dangerous for the dogs and people. Many people are scared of dogs, some for good reason, and it's terrorizing them to have dogs running around loose. People can't tell just by looking at a loose dog, how well-trained and socialized they are.

Responsible dog owners, like myself, resent the self-centered owners who think they can do as they please in public areas. They are a threat to my dog (hence the ever-present pepper spray -- a non-lethal means of defense).