There are a couple ways to freshen up the cargo nets. First, you can adjust the sagging nets by taking up slack on the formerly elastic cord a the top of the net. Go to a dry goods store (sewing supplies) and buy a pair of plastic toggles that are used at the bottom of windbreaker jackets or on drawstring bags. Run a loop of the cord through the toggle and then you can loosen and tighten it as needed.

The second way is to replace the netting and frame with either a OEM part or a good one from a breaker yard. It's removed by sliding off the seat back, which is held in place by two screws at the bottom edge of the seatback.