Mortgage lenders are seeking relief from Fannie Mae and Freddie Mac as the government-supported companies force them to buy back more soured debt, said John Courson, president of the industry’s largest trade group. While his members “certainly understand” their contracts require repurchases of defaulted loans when items such as faulty appraisals, inflated borrower incomes or missing documentation are discovered, the Mortgage Bankers Association has started to “aggressively” push the two companies and their regulator to ease up, he said.