Guys, i did not read through this entire thread, but i had same problem, i complety fomated my HDD and reinstalled everything from scratch. That did not help me, i thought it could be my HDD getting corrupted (reason why i thought that is becuase whenever "unapproved caller" showed up at same time everything on my HDD went read only mode). Hence i replaced HDD and put in new one, i dont get unapproved caller anymore.
But there is still a problem somewhere, becuase my MBP freezes and HDD goes to read only mode, the only solution is to restart my mac sometimes multiple times.
I think both these events are mutually exculsive.
I have been troubled with this for about week now and very much gave up all hopes on my MBP.