Treasury secretary Timothy Geithner on Thursday slammed mortgage service companies for failing to do enough to help Americans avoid losing their homes and promised to crack down on shoddy practices. “We do not believe servicers are doing enough to help homeowners — not doing enough to help them navigate the difficult and frightening process of avoiding foreclosure,” Geithner said in prepared remarks for delivery to a Senate appropriations subcommittee. He said Treasury was “troubled” by reports that servicers had done things like foreclose on homeowners who were potentially eligible for relief under the government’s Home Affordable Mortgage Program, lost documents or claimed to have done so and even steered troubled homeowners away from available assistance.