I used to work for a kitchen ware manufacturer that had (at the time) recently taken rebate processing in-house after problems with their contractor.
Yes, most outfits that use rebates use contractors or other third party agencies to handle them. The better companies will follow through on your behalf (as happened in this case) although sometimes you have to find the right person. There are many good business reasons for this (which are too lengthy to go into here) but like anything else, there are trade-offs involved. Including contractors or contracting firms that don't give a damn.
Rebates are not per se "sleazy," but do require some effort on your part. If you don't want to deal with them, buy another product or ignore the rebate. They do figure that 40 - 60% or more of the people eligible for the rebate won't bother to apply for it or won't do it properly, that is figured into the cost.
Based on my work with the aforementioned prior employer (I helped the rebate team out with some various IT & mailing issues), some tips:
1. Read the coupon or directions carefully and follow them. FOLLOW THE RULES!
-- If they ask for the UPC barcode, for example, send them that.
-- If they ask for an original, send them an original, not a copy. Many stores can give you a duplicate receipt on the spot for rebate use, incidentally.
-- Provide EVERYTHING that is asked for. If one item of 3 or 4 is missing, you may not get your rebate.
-- Use the right coupon! Some companies have two or three rebates going on at a time... if you get the coupons mixed up, you may not get your rebate!
2. Make and keep a copy of EVERYTHING you send them.
-- and with that copy, note the date you mailed it.
-- also, if there is contact or follow-up information on the coupon, make SURE you keep a copy of that as well.
3. Use the right address, enough postage, a proper envelope. And mail it right away, don't wait to the last minute.
4. Allow plenty of time for the rebate to arrive. When they say "allow 6 - 8" or "8 - 12" weeks for processing, they ain't kidding. Many of the rebate processors are small businesses, and only have a handful of people to handle the mail. I saw bins of letters sitting literally for 6 weeks between the time they arrived & the time they were processed, but the rebate group was only 2 people!
5. Use the right return address. Many people in less populated areas have a street address that the USPS does not deliver to... or have a PO box for mailing that FedEx & UPS can't deliver to... and so forth. The rebates often get returned or "lost" if they are undeliverable. We once had a guy getting very upset that his kitchen knife wasn't being delivered to his work address (at a college campus in CA... hmmm...) Turned out that his building, even though it had an address, was listed in the USPS database as a non-deliverable address -- all mail had to go through the campus's mail facility, which distributed the mail to him. (Also turned out that he didn't want to use that address because the school's mail system wouldn't deliver a knife... we finally got it to him via his home address, more than that I don't want to know!)
6. If you have to follow up, be polite. Threats of lawyers, TV investigative reporters, the attorney general... get laughed at, especially on the first call. (I loved the one from the guy who threatened a class action lawsuit because the rebate form clearly stated that it was NOT valid in Canada, which he claimed was international discrimination!)
-- BTW, more often or not, the louder and more threatening the call, the more likely that the person didn't send in the rebate correctly or on time.
-- But, if you overlooked something, and honestly made an error, and plead your case nicely, the person on the phone may be so happy that you're NOT screaming at them, but being reasonable, that they may just be willing to help you out and get you what is due. Again, I saw this happen time and time again.