MCI is, IMHO, The Biggest Ripoff Artiste Universwide. They'll promise you anything, but getting them to deliver is another thing. Now, I bear them no ill will, and have had their long-distance service for years without playing (too many) games on the miles: but their cellular service stinks ROYALE (have you yet gotten a correct billing?), and THE ONLY reason to re-sign with them is the UA 5000 miles.
Surprise! I notice you are also from Northern California. I've been told REPEATEDLY by them that my TWO phones will not be provided with the 5K miles. After calling around to numerous MCI offices, finally they said the Bay Area didn't qualify since they don't really own the system (CellularOne does, they re-sell). Now why this should matter, I don't have the foggiest. But I've given up.
If you manage to actually get this, let me know how by posting here, please. But don't hold your breath!