G- just wanted to add that you're not behind in the process, in my opinion. Umass doesn't have the typical rolling admissions. Well, they accept a few stellar candidates on a rolling basis, but most people have to wait till March-April. I know many people who interviewed in Oct/Nov but then weren't rejected or waitlisted until April. I don't think anyone who interviewed earlier has any advantage over you. If you impress them at your interview (whenever that may be) and have imprressive qualifications they will accept you right away. I guess my only concern is that you get an interview before they send out the bulk of acceptances, but I believe that they stop interviewing before that happens--you would probably know better than me about that.
Cand-- I know that AMCAS has been GROSSLY incompetent this year, but at a certain point you really need to take matters into your own hands. I feel (like many others on this board) that I would never have gotten verified if I didn't bug the hell out of AMCAS, calling every day, talking to supervisors, threatening them (nicely) etc. If you need the names of some people that can help you I could give you some contact info for them. But you really need to act now, unless you only applied to non-rolling admissions schools.