I'm having the same issue. I am verging on a full-blown panic attack as one of my recommenders still hasn't submitted her letter despite a number of reminders from myself as well as the graduate admissions office. My other two recommenders submitted their letters so at least I have the minimum required, but I am so very upset that I am being ignored by this person, so much so that I am reconsidering attending the uni (where she works and where I am currently enrolled as a post-bacc) due to this very negative experience. I'm only a student, but I feel that as a professional, one should follow through on commitments made. Barring that, basic communication would be nice. My marks are top-notch, GRE scores excellent, but I have a very diverse resume due to multiple international moves. I can't imagine that this would warrant being ignored, though.