Usually an easement is only granted if the people needing it are land locked. Also if they knowingly purchase land that is landlocked at the time of purchase and there is no easement in place. They are just out of luck. They can't make you give em an easement.  If they aren't landlocked and can get to this property by another roadway. Id think it was time to remove the easement and get access to your property on their part taken away.

If you can't do that, Id fence the easement so they had to follow the path intended.