Awwwww Mannnnnnn.........That's the pits I would send it back with a little sticky note asking to test fire the weapon before they return to you.
Like Bud says, It could possibly be a mag catch, which is an easy fix, and hopfully nothing more than simple fix is in order. I hate it when I spend big money for something, and it fails me on the first go-around. I do understand everything may be flawed, but when you get replacment parts from the factory, and they still fail you, time for the Company to take a look at the component suppliers. Personally, I would feel better knowing a weapon was test fired prior to leaving the facility, and test target results were supplied in the box. I hope they go right thru it and the gun comes back all fixed and better than when you sent it out. I'm looking forward to seeing your re-test of the weapon when you get it back Good luck