The part may have been recently discontinued or may be on a back order for an indeterminate amount of time.
That is highly unusual. I had the whole store looking for a heater for a full 15 minutes and neither they nor another store they called could find the thing their system said they had. I had it at 9:30 am the next morning bc they ordered it from where ever. It was impressive. Try eBay for old parts.
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