Bring all the papers to a local MT lawyer. It's not clear if your down payment was to the sellers of the house, or if you made some advance payment to the internet lender.
Nobody can advise you without reading all the documents. And print out screen shots of all the web pages, too.
Start with a review of the documents you and your husband signed. They'd govern the parties respective rights and remedies, and would define the scope of work, what the down payment was for, how and where you can resolve any disputes that arise, and which state's law governs, which is probably MT.
Then find a litigator to disclose all the details of your situation. If this was a mortgage loan modification or refi scam, you may also want to contact MT's Attorney General or your city's City Attorney to see if there's a criminal investigation about this company.
I'm only licensed in CA. Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.