I'm assuming these are mail-in rebates, where you have to manually mail out an envelope containing filled out forms and the UPC codes, or what not. if they're not just ignore this message.

I don't know how much you've messed around with mail-in rebates before... But expect a good chunk of them to claim you did something wrong or to claim they were lost in the mail. I would also suggest making copies of all the receipts and UPC codes, etc, and noting when you shipped the rebates and keeping pertinent contact information, in case you need to reship due to a supposedly "lost" entry.

Mail-in rebate centers are often very poorly run just in an attempt to cause things to be lost so they don't have to refund the money.