If a neighbor is complaining to the police about you over something that isn't even happening. Do they have to prove the guilt or are you responsible to prove innocence?
I should have said neighbor not neighbors. It's only one
You don't have to prove anything and they can't prove guilt if you didn't do anything. Most often the police will ask you your side of the story. If you say you didn't do it and they didn't see it they won't do anything to you. Most often they will try to calm things down by speaking to the neighbor.
The cops do a quick investigation. If ONE neighbor complains and no one else does, then it is his word against yours and since you are innocent until proven guilty, they go no further with the issue.
However, if there are a BUNCH of neighbors who complain then it is a BUNCH of people against your word. If one of them has a video tape or some other evidence of what is going on, then the cops quite likely will issue a citation against you. In that case you had better get a lawyer.