@4Banger have you consulted an attorney? It sounds like you tried to resolve this in a gentleman fashion. But that isn’t happening.
So bring your contract to an attorney. Have them review and provide proper direction.
There have been numerous responses on this post. We’ve all heard you. Members have even done field recon work to assist you. I’d stop “harassing” John altogether until you consult an attorney. That may be the only next step in your future to providing resolution.