Seat Belt Replacement Needed

For some reason, the pretensioner for one of the rear seat belts in my 2000 Passat spontaneously activated. Has anyone had that happen? So, I need to replace the belt. Specifically, I need to buy an outer seat belt assembly, beige, for the left rear seat for a 2000 Passat sedan, Part No.3B5 857 805. A local shop was able to find a recycled seat belt but it was gray and I need a beige one. I've already searched several VW parts websites without success. Any ideas as to where one could be located? Thank you!