As a founder, I've got sales guys cold calling and emailing me all day long. They are usually new, and completely disconnected from the realities that a startup founder faces. They also generally lack the authority to make decisions, so the call always ends up as a waste of time.
Who do you want to talk to then? Unless you're a big customer, the founder or VP of the company selling to you is probably (understandably) too busy to talk to you. If they really want your business, the sales person will escalate it appropriately. If they don't want it bad enough ... they won't get it.