Contact your mortgage company and title ins. Co and get the site survey that was done to get title insurance. Review it, find the stakes (paint them clearly and then file a claim with them. I did that and Home Savings (MO) bought the land in question from my neighbor and covered all costs.
I would say that a letter from your title insurance co to theirs will have them knocking on your door with little delay and in a amicable manner wanting to resolve the problem.
You will get nowhere with a claim for maintaining a property other than your own in court but if you like legal receipts, go for it.
__________________
|