Should I take my neighbor to court over a property boundary dispute?

Without notice, our neighbor placed landscape timbers on what we believe is our property. When questioned he said he had a survey, and showed us two nails on either side of his property, from which he drew a string. When asked, he said he wouldn't share his survey documentation because had paid for it and we had not He did give us his surveyor's name. Turns out he has an improvement location certificate, not a survey. No surveying pins were placed. He won't move his timbers and they're almost two feet over the line between the common sprinkler heads in 3 separate properties and the original landscaping materials around a tree in our yard; original being since 1995.