Steven and Tamara Gewecke are three years behind on their mortgage payments, but they've fought off foreclosure.The Minnesota couple refinanced in 2006 to start a business. It failed. Debts mounted. The Geweckes went bankrupt and failed to win a loan modification. But they bought time. In 2009, the Geweckes filed a lawsuit to block their foreclosure. At the heart of their case is this question: Who owns their mortgage?