I've had a problem claiming a Whirlpool dishwasher rebate for a dishwasher purchased from homeverything.com. The industry organization the rebates were run through bounced mine back, saying it had not been paid for. They wanted an invoice marked "paid in full", even though the machine was paid for with a credit card, had been delivered and installed. They didn't respond to an email sent to them at firstname.lastname@example.org.
Had to get a different invoice from the online seller, re-send it by US Mail to NECO Alliance, and have been waiting for three weeks with no response.