Imagine you worked for one of these companies and every week you get another couple companies asking for product/samples for free because they have this awesome idea, etc. They roll their eyes, press delete and move on. You need to give them a reason to think you'll be successful. Traction (we have X committed customers); Financing (we raise $Y money); Team (I was the Emir of lipstick at Nordstrom); Social proof (here's an article about us in the Sample Box Journal).
My wife just launched a subscription box company and companies basically yawned when she initially contacted them (not even for samples but to buy stuff!). Then she gets a great story in a large circulation pub that she then sends with her emails and all of a sudden companies are falling over each other to help. Look, people are busy, overwhelmed with requests and have zero incentive to spend their time helping you... until it's clear that doing so will help them.
So come up with something compelling and get on the phone. A form email sent to info@ is likely to be ignored. You find the right person and get them on the *phone* and now you've got a chance to sell them.