A private contractor is accusing Bank of America of deliberately blocking aid to struggling homeowners by preventing loan modifications while still receiving government assistance under the the federal Home Affordable Modification Program. The contractor, Gregory Mackler, says he witnessed the practice while working with Bank of America executives at Urban Lending Solutions, a company contracted by the bank to handle some of its loan modification business. According to Mackler, Bank of America officials regularly pretended to have lost homeowners’ documents, failed to credit payments during trial modifications and intentionally misled homeowners about their eligibility for government help. On Thursday, members of the group CodePink were arrested at a Bank of America branch in New York City while protesting the company’s foreclosure practices.