Well, I thought I would come over here one last time to let you all know, the saga has ended. Sharp sent me my refund.
They also included a form letter, informing me that:
"...all contracts for the purchase or lease of goods would be awarded through competitive bidding, negotiations....a purchase order number will be required...form W-9 must be on file in Corporate Purchasing in order to process and payment. These changes will be effective January 1, 2007."
They apparently can't even keep sufficient records to recognize this is a refund going to a consumer, and not a "supplier". I'm glad I don't have a business relation with them. They must do a lousy job or tracking records!!
Best of luck to everyone. May you be fortunate and not have to deal with Sharp.