Shoddy paperwork, erroneous fees and wrongful evictions are cropping up among the servicers that collect mortgage payments. Servicing companies like Nationstar and Ocwen Financial now have 17 percent of the mortgage servicing market, up from 3 percent in 2010. The servicing companies are unfettered by many regulations which apply to banks. Because of those regulations, banks are eager to hand off some of their more challenging loans. Federal and state regulators worry that the rapid growth could create new setbacks like stalled modifications for millions of Americans. Analysts say the specialty servicers have not upgraded their technology or infrastructure to accommodate the glut of new mortgages. Some regulators say the servicers benefit when they work through the troubled loans as quickly as possible, raising questions about whether the companies are pushing homeowners into foreclosure.