It's not just on the customer side. My mom, an Amazon seller, has been trying to get in to list her stuff since about two weeks after Jet went online. No response at all.
They were at Channel Advisor Catalyst, a trade show for e-commerce channels and services. We do shipping auditing and were exhibiting; they wouldn't give me much chance to chat with them. Not that they need to talk to me, but for the nature of the trade show, it felt like they were less interested in talking to vendors and potential partners (the point of that show) than press (since the show is b2b, not b2c)