I worked for a large outdoor product manufacturer that sold into stores such as Target, REI, Dick's Sporting Goods, Cabela's, etc.
As you can imagine, if you are not one of their regular suppliers, getting even 5 minutes of the buyer's time will be no small feat. Depending on what market your product is in, I would work to identify who the correct buyer is at that company for your type of product and try to find out the best way to reach them; e-mail, phone, etc. Have your elevator pitch ready should you happen to get them on the phone and hit them with only the pertinent information about your company and the product.
If you can identify any industry trade shows they may be attending and either set-up an appointment at the show or outside of it, this is a good way to get some face time.
I have some other ideas that I'd be happy to discuss with you on a call if you'd like. Be persistent. Be polite. Don't get discouraged if they don't get back to you right away.