I have an existing walkway (~80 feet long) with 6 steps up a slight incline in my yard and during the past two winters (I live in Massachusetts) the pavers have started to settle – especially closer to the steps in each tier. I’m not sure if this is due to general washout or something else. The ground foundation is very rocky and solid so the contractor didn’t put down a deep base under the pavers – just a bit of poly sand. The steps are also a bit wobbly – they are made of two layers of paver stones glued together.

Questions: should I pull up everything and put down a cement base and then add sand and pavers? Should I simply pull up the sinking pavers and add base material? Should I add some type of permanent border (under ground at edges) to prevent potential washout? help please…..
More info: the original work was done by a contractor in 2007. I live near Boston so we experience freeze/thaw cycles.
What kind of border are you talking about? A flexible plastic border, cemment, other?