Vito Corleone

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!

It seems fairly suspicious to me, that the one thing that stops police from investigating, a note, was provided. Have they not heard of notes being written under duress?

I am not sure he cares. Because his neighbor is her cousin and would know where she is.

Has the OP considered hiring an attorney and perhaps more importantly, a private detective to ascertain her true whereabouts? Might be a long shot, but may turn up something for the purposes of getting this thing sorted out properly.
For all purposes this is a marriage that can be considered abandoned on her part, so he can file for divorce without her signing anything and move on eventually.
But if there is any care about her safety and well-being, contacting the human trafficking division may be prudent.

I bet the cousin is in on it, but I would first have that conversation to see if they seem uncomfortable or concerned, the get the cops involved and have them question the neighbor. Or something. I would do something more than texting "hey you have to come back for ROC."

There's only one real Don and that's me Don Vito Corleone. Kiss my ring!