elizabe

Hi, I asked three professors for letters of recommendation about two weeks ago and all agreed pretty enthusiastically. One submitted his right away, but I am having problems with the other two. One said he was going to do it this past weekend but has not yet submitted and the other has not responded to the last three emails i sent him about 1) the details of schools i am applying to and 2) my resume and personal statement 3) a reminder and request for his address to send him something for the holidays. I called him this morning and left a message but have not heard anything !?!?! Did i do something wrong? I am banking on the fact that I have read most schools allow a little leniency in the lor deadlines. But what should I do about the nonresponsive professor? ! Do i interpret is silence as a tacit understanding that he no longer wants to write the letter? Should I try to get another recommender, or can I even change it at this point? I know that was like five questions in a row, but can someone please help me out here with some advice. Thanks so much!