From the sounds of the tapes released, it seems as though Mesaba was trying to work with XJet. It's not as if they out right refused to help and were bullies about it. So... it sounds like there is even MORE to this story we don't know.
My FO's and I have discussed this issue many times and this was certainly a tough place to be. I think however, if I were in the same shoes, I would have rolled my proverbial sleeves up and gotten physically involved somehow. Perhaps jumping off the plane and going inside to talk face to face with the Mesaba people to solve the problem. Face time gets you much further than radio time. And before people start talking about how there are no air stairs on the ERJs... there weren't air stairs on the avro, which also was high enough to need slides. That didn't prevent me from jumping out to make things happen in the past. There is always a solution to every problem.