By Jim Loney

MIAMI (Reuters) - Gabriellee Cunningham had fallen behind on the mortgage on her modest suburban Miami home and was mired in debt when she was approached in June by a door-to-door "mortgage lender" who promised to help her.

Nine months later, her $89,000 mortgage has ballooned into a $234,000 loan, her monthly payments have doubled and she faces foreclosure on a house she no longer owns.

Housing officials call Cunningham the victim of one of the worst cases of predatory lending they've ever seen and warn, as the U.S. subprime mortgage crisis grows, of a rising tide of scams in which homeowners are being cheated out of their home equity.

"I know I did something stupid but I am going to fight these people 'til my last breath because they are trying to rob me," said Cunningham, 48, who works at three jobs. She says she fell behind on her payments while trying to fund college educations for two daughters.

Consumer advocates have seen a surge in "foreclosure rescue" and "equity stripping" scams in recent months as the subprime mortgage crisis developed.

Lenders launched foreclosure actions against more than one in every 200 mortgage borrowers in the fourth quarter of 2006, according to a Mortgage Bankers Association survey that hammered equity markets this month.

That figure was the highest in the association's history. Subprime adjustable-rate mortgage delinquencies jumped to nearly 14.5 percent in the quarter.

CRISIS JUST BEGINNING?