Forbearance with GMAC

I live in southern California and own a home in Pennsylvania. The home in PA past due is about $14,000. I got divorced in about 2005. The home in question was not part of the divorce settlement in any way. My ex-husband continued to pay the mortgage payments and his father lived in the home. Several months ago I was informed that he stopped making the mortgage payments. At that time, I called GMAC and they told me that nothing could be done unless I supplied my ex's financial information and tax returns which I was unable to do- I have NO IDEA where he is and no way of contacting him. I want to keep the home but it's not possible because I cannot supply his information. What I would like to do is work something out with GMAC to pay the past due amount (a down payment and installments, if possible) and relocate to PA have this be my primary residence. Is that called a forbearance? If you can help me or know of anyone that can, please contact me.