I need help! Are we getting the run around in this real estate matter?

We had our house up for sale, we accepted a contract on it saying that the buyer had til on or before 9-29 to close on the home. 9-29 came and went and our realtor said that the loan company was tying up the paperwork. He said he called them directly and they said it was out of ';Underwriting'; and that he had received a copy of the ';commitment letter';. Our realtor says he has had the buyers ';commitment letter'; for one week and a day. As of today we are no closer to closing on the home. They (being my realtor and the title company) keep saying that they are waiting on the mortgage company to finish with it and send them the packet they need to send to the seller to sign off on. What I dont understand is why this has taken over 30 days and why we are no closer to closing this week than last week. Does anyone have any ideas what the problem could be? If you need more info and feel that you can shed some light on this please feel free to email me at bdogz6@yahoo.com