Mazda Repair: 93 mazda miata harmonic balancer, mazda miata, drive pulley

Question
I purchased a 93 Miata, the harmonic balancer is making noise, took it to the shop, they tell me that they cannot locate an identical match harmonic balancer.  Please instruct me on the steps I take to identify and find the correct balancer.  They tell me that they went to a Mazda dealer and are unable to find a match.  PLEASE HELP.

Answer
I have never seen these drive pulley assemblies fail.  Was the item struck by impact or possibly dropped.  At any rate the replacement part number is B6S8-11-401 (mazda) cost estimate $146.  Mazda distribution has them in stock.  Confirming: Balancer as some call it, it is the crankshaft main pulley with drive grooves for the alternator and AC belts.