There are companies in the USA that can 'Rebuild' the seatbelts and issue an 8130-3. This includes re-webbing, and inspecting - replacing as necessary (IRAN).
I've had mine done and so are a number of other folk who have contacted me.
As long as the belts have their TSO tags, there isn't a problem.
As per the Cessna Manual, rebuilt seatbelts are allowed to be refitted.