It would help if you had a local lawyer help you out since there are other reasons for foreclosure apart from failing to make payments. They may be foreclosing due to unpaid insurance, taxes, state of disrepair, diminution in value due to market conditions or alienation without authorization. Other than that a dispute letter needs to properly identify the parties, the property, acknowledge the basis for the foreclosure and provide every defense to the foreclosure that you can think of including defective or invalid service of process if your husband is deployed. They may have omitted or failed to submit a valid military affidavit. Best to check with a lawyer so you do not mess this up.