My question involves real estate located in the State of: washington state.

My front yard is adjacent to a neighbor’s front yard. My previous owner had same boundary line problem with this neighbor before. Finally they gave up and sold the house to me. The neighbor is redoing his front yard now which I think he is working on my property. There is a metal pin on the front yard. I got the plat map. I asked the guy if we can measure the angle&length together so we can identify the boundary line, but he was very rude and insisted that’s his property. But he didn’t have any proof except a Google map. My husband is not in US. What should I do? I like to get this straight out. Which court should I go? Do I need the survey done first? If they lost, will the court ask them to pay the survey fees?

Any help is really appreciated it.