I've recently seen Mesaba reject some really good candidates, and then take some **** poor candidates. I know an 1100TT Falcon driver from a 135 Company that got the same rejection as you. I also know a 450TT 7.5Multi Flight instructor that is starting training in the next month. Both guys applied the same way and didn't know any higher ups at Mesaba. I haven't been able to figure them out yet.

There are other places in Puerto Rico that might pick you up for some right seat time. You can try Air Tahoma (not sure how to contact) or Mountain Air Cargo (they've got a website for sure).

The regionals are slowly starting to hire again, but you know there's really no money there, just time. I would start handing your resume out to every part 91 op on your field or even in your area. Corporate just might take the jump to pick you up with your management background and they would pay a lot more.

Good Luck!