How do I find out background information about people?

I work for a storage company and we want to find people who owe us money so they can pay us.|||what information are you looking for? which location are you at and which country? In canada we have 411.ca, there's also special software you can get. Or if you're in the states go to http://www.delta1inc.com/govinfo.php You can get government listings on just about everyone dating back years and years. Maybe you can pinpoint their last location so you can collect your money or at least find their relatives.