We can certainly understand that this is a distressing situation for you and others, both in terms of your access to the bay and also of the social relationships in your community. How to resolve it? Based on what you have described, this clearly seems to be a legal issue, and one that would need to be resolved by the legal system, especially if prior discussions have failed. In this case, while keeping communication lines open, we would strongly suggest you and your neighbors consider getting legal representation and pursuing legal action.