Front Seat Belt Buckle Assembly problems of the 2001 Mercury Marquis

I am reporting the failure of the buckle on the front seat belt on driver's side of vehicle. It appeared to click"closed but unexpectedly popped open when I driving. I contacted the manufacturer . Who said that the vehicle was not under a recall for this problem due to the VIN. . However, NHTSA site showed that there was a recall of the vehicle for just this problem. I understand that recalls were typically assembly plant related and that this vehicle might not have been included in the recall. However, the similarity was too great to ignore ,and I wished to report this matter to you. Please note that no accident occurred but the hazard to my safety was considerable. I will replace the faulty part at my own expense in the meantime but urge your agency to further review the possibility that not all the vehicles so impaired have been recalled. Latest incident occurred on April 7 but was preceded by many more.