We’ve got a solid MC and work with a lot of brokers, so we were surprised when this brokerage wouldn’t work with us. The guy on the other end just said, "Oh, we’re not set up, so I can’t work with you," and that was that. I asked if we could work things out and prove that we are a reliable carrier, but he didn’t even consider getting things set up.
If you’re not already in their system, don’t waste your time calling. It’s frustrating to deal with a company that isn’t willing to be flexible or even explore options with a reliable carrier.