Does your area have a tree warden? Towns in New England typically have an appointed tree warden whose main responsibility is the health and safety of trees along public ways and on public lands. But, at least in small towns, they're also usually willing to show up and give advice in cases like yours. I've known the warden in our town since our 35 year old kids went to middle school together. If someone in your situation called he'd come over and either fix the problem or tell you who can fix it. He'd also likely know all the parties involved in the SNAFU.