An online lender that had promised to revolutionize the mortgage market by guaranteeing borrower costs, LoanGiant.com, is fighting for its existence in Michigan, where a rising tide of consumer complaints has led to an effort to revoke its license. One of a handful of online-only non-prime lenders to spring up during the Internet boom of the 1990s, LoanGiant made its name with an automated process that officials said would help wring costs from the