Are you facing foreclosure, or have you been sent a notice of foreclosure with a sale date?
Is the notice from the servicing agent (i.e. GMAC) or is it from an attorney on their behalf?
What is the history and status of your verbal and written communication with all parties as of now?
Has your property been properly advertised or not? In the state where I find myself, a foreclosure sale requires four weeks of sequential advertising of a property before it can be made available for sale. Check either the servicing agent's website or that of the law firm. They probably have a foreclosure page. Make them prove it has been advertised properly, or - better yet - prove that it has not without even having to ask. If you ask, they will.
If you do not see your home listed there, assuming you find their listings, then take a snapshot of their website and save the picture for your files. Do this every other day until the issue is resolved.
Free 30-day software trial to make this easy is here:
http://www.techsmith.com/download/snagitfreetrial.asp
If they try to force the sale without advertising, they have broken the law.
If they try to force the sale to collect a debt which has not been validated to the penny and according to GAAP, of course only if you ask for this, then they have broken the law.
If the law firm tries to force the collection of an amount without validating it to the penny, and debt collection is a primary source of their business, then they must obey the Fair Debt Collection Practices Act and all holdings related to it. You will have to know what they are supposed to be doing so you can call them on it, otherwise they may forget. The law firm should also be able to provide you with a copy of an invoice including services rendered for which you are responsible to them directly, otherwise you have no CONTRACT with them. Which means you don't own THEM anything. Unless you make one. This is why they have written you.
I have uploaded a massive amount of case law that applies to the FDCPA. You can find the act itself online and read through it. It's not complex. There are cases in the files I uploaded which hold that law firms collecting debt are "debt collectors" pure and simple and that they must act like every other entity trying to collect an amount allegedly due. They do not get any special treament on the street, like they do in the court room. But you have to know this and how to use it.
Welcome to your new second job! You will find a massive amount of support on this forum.
I have a very full day but I will check back in some time before I go to bed if I possibly can.
Take a deep breath...