Unfortunately this has been a reoccurring theme with certain lenders. There are those that promote 600 and up and I can do your loan. While programs exist to allow this, the problem is that this is not a slam dunk. The risk tier associated with borrowers have a FICO score below 620 don't allow for a FHA score card accept unless there are compensating factors. Compensating facts would be increased down payment; meaning more than 3.5% from you of your own funds; more than 3 months reserves and a current rental history paying more than what you currently pay. If you don't have any of these compensating factors, then you should focus on getting your score over 620 before making application. DO NOT PAY FOR CREDIT REPAIR.
As for the "commitment from the lender", True commitment does not come until everything is complete, this is a common mistake made by all in the real estate community; lenders included. True commitment is title, loan and appraisal approval. Once you have a "clear to close" and an approved HUD-1 can true commitment take place. Often contracts require a date to remove financing contingency; this does not mean loan commitment. Unfortunately you have no recourse against the lender, accept to request the transfer of the case number and appraisal, before you spend more time and energy make certain that you have had your file reviewed throughly. I would advice you to seek the advise of three lenders, you do not have to have your credit pulled three times; have a copy of your most recent credit report, w2 2010-2009, 30 days paystubs and two months source of down payment; if you have a 401k make certain to provide the most recent quarterly statement as well as the terms of liquidation (contact HR for the terms of liquidation agreement). Talk with all three lenders and listen to the one the makes the most sense. The words "NO PROBLEM" should not make you feel comfortable, they should make you run.
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Bank of America Home Loans