I rent out a condo.

The master bedroom has a closet with sliding doors & built-in drawers/shelving. It's a regular closet (not a walk-in closet).

The downstairs neighbor complains that the closet Doors & Drawers make noise when they are opened and closed -- starting from 6am onwards... I've already replaced the closet door tracks and rollers once, but the neighbor says he still cannot get a decent night's sleep.

In order to reduce this noise, the neighbor wants me to "install a layer of insulation cork below the [closet door] tracks" and "at the base of the built-in cabinets inside the closet." The cost would be $590.

Please advise.
Thank you for your time and expertise.