I agree with much of the above comments here. I have found it usually takes initiating and sometimes actually following through with foreclosure in order to get the borrowers to communicate. You will experience the occasional borrower that will contact you after the shock package or demand letter. But for the most part they tend to wait to the last minute.
I have a borrower currently who has completely avoided communicating with us even though they have been notified the foreclosure is taking place next month. They have been served papers personally by our Attorney's representative as well as a peace officer. This was handed to them at their doorstep. In the scenario I described, the borrowers are still paying faithfully on the 1st mortgage so I know they are planning to stay in the home.
Borrowers oftentimes wait until they are just about to lose the home or being evicted before doing anything about it, especially with 2nd liens. I would recommend simply moving forward with legal and letting your attorney handle the rest. If they are paying and current on the 1st mortgage just move forward and let legal bring them to you or take the property.
Josh