I'm going to assume you have formed a legal LLC or Corp. I will also assume you've obtained an EIN and Duns#. I've been there, I know how frustrating it can be. You have Quill and MSC Industrial, so use, pay and get some history reporting with those 2 accounts. After those 2 accounts have 3 to 6 months of history, try again for Supply Works and Grainger. Your business really needs 15 months or more of history before you'll see approvals. Citi backed no PG cards will require 3 plus years of reporting history, and a PG'd major of 2 would help with that as well.
Hang in there and wait it out and I'd be willing to bet you'll see approvals for Amazon net55 and Lowes net 30 after 12 months or so of history.