It would be nice to not have this escalate further. Any chance of trying to train the pup to not charge? Stop and give it some really good treats? (Too bad it is even harder to train the neighbors. You could consider telling them that you are sorry things got off on the wrong foot and ask if is there a way for the two of you to work together so that the pup does't charge you? It might deflate him a bit.)

I understand the option of calling the police but it may be better as a last resort as it could escalate neighbor problems further.

Good luck! Nothing worse than neighbor problems.