Once you got rid of them as per robina you need to prevent them from access to the lines again. Maybe some Vaseline or grease around the posts, just above ground level so your washing won't flap on it.
If the end of the line(s) are attached to a building or the house, try a 4" circle cut from a plastic ice cream container with a cut halfway through to a hole in the middle that would fit snugly over the line - like those things they put on the ropes that tie up ships, to prevent rodent from climbing up to the boat. Put one on each end of the line and the [auricle]wigs won't be able to reach your washing.