First, try to talk with the surveyor who did the work.  Most surveyors are willing to spend some time explaining the property line to a neighbor, although their schedules are often very busy.  In establishing a property line, a surveyor is always aware that it has two sides.  The surveyor will make every effort to locate the line in such a way as to respect the rights of neighbors.
Then, if you are unable to contact the surveyor who laid out the line in question, or if you don't understand the explanation provided, you may need to hire a surveyor of your own to check the line.
Whenever there is a question or dispute about a property line, be sure to mention that to any surveyor you are thinking of hiring.  These situations often involve extra work, and it is best to inform the surveyor in the beginning. This will prevent a misunderstanding about the cost later on.  Some surveyors prefer not to work on disputed property boundaries at all, partly due to the difficulty of predicting the cost of such work.