The number of New Yorkers filing claims with the attorney general’s office to break contracts on homes and get their down payments back has tripled in the past two years. By February 20 of this year, the office already had 74 claims. There were 168 filed in total in 2008, and 57 claims in 2007. Real estate lawyers say the traditional method for a buyer to break a contract is to prove some element of the completed unit differs from the developer’s offering plan. Some buyers trying to get out of contracts are calling on a 41-year-old consumer protection law that requires developers of condos with more than 100 units to provide buyers with a property report containing information like proof of ownership and availability of public utilities.