Unable to get work experience letter work for more than 1 year?

Hi all,
I have been facing critical condition that I have worked for one software company since 2010 Jan to 2011 jan legally. Because of lot of work pressure and torture I left job sending resignation. When I asked for experience letter they said they don't give. I had not signed any bond papers. Please somebody help me without experience letter its difficult to find new job more than that I don't want lose my experience letter. What to do...Please help....!