In trying to get Walmarts to carry and sell your new product, Maybe you don't "pitch" on the product itself. Remember, "people do things for their reasons, not yours"(c, ndlicht) so instead first carefully understand what each listener cares about in their role. Having done so, start off relating right up front get them involved, seeing how what you propose can help them or fit in with what they do.
Start off with stating some of these issues and how what you are offering makes those issues go away or become non-issues. They then are ready to hear you out based on knowing that what you will say directly relates to them, won't make life more difficult, can help them in their jobs and easily fit into their way of doing things if your proposal is adopted.
Not so obvious example: Distribution director is worrying about how to get and then easily distribute your product withing the Walmart system- address that as part of your "pitch". See what I mean. Folks on the listening side who are not directly involved in retailing to the end user but do have a say now or later can then say OK to your pitch and help you get accepted.
Try it out - do that homework, learn who will be on the listening side of the pitch, and who along with them is also involved in giving you to OK. Then, knowing that ant the motivations od the listeners, retool your opening to involve each, pitch and close accordingly so everyone can and will say YES