First, I hope that isn't your only defense, because I'm not sure it's that viable. You should check with an attorney to be sure though.
Second, you're rapidly running out of time. If the sale is to be enjoined, from memory that needs to be done 10 days before the sale date, and that doesn't mean you can contact an attorney on the 11th day. You need to find an attorney today. Unfortunately, other than refer you to real estate attorneys, I don't know of any that specifically do this type of work.
Also, if you have a first and a second, and the second is completely underwater (e.g. first is $300,000 and the house is worth less than $300,000), you might want to consider a Chapter 13 bankruptcy. It may be possible to entirely wipe out the 2nd as a lien, and give you time to cure the default on the first. Email me or call if you'd like the names of some bankruptcy attorneys.