Marjorie Sener was still in her 20s when she took out a loan for about $5,000 to get some college credits she hoped would eventually add up to a bachelor’s degree. That goal was thwarted when her partner became ill. “The burden of our living expenses fell on me,” said Sener, who lives in the Dallas suburbs. “I devoted all of my resources to keeping our heads above water.” But while Sener never got her degree, that student loan kept growing, fattened by compounding interest.