If you have lost your contacts on your Blackberry, there is also a way to restore it as long as you have previously synchronized your phone with the BlackBerry Desktop Manager. Here are the steps:
1. Connect your Blackberry to the computer on which you have the BlackBerry Desktop Manager installed. Launch the Desktop Manager software.
2. Select "Backup and Restore," then click on "Restore."
3. Locate the backup file with your contact data. This file will be in the default location unless you have previously changed it. For Windows XP this is C:\Documents and Settings\\My Documents\ and for Windows Vista and Windows 7 it is C:\Users\\Documents\
4. Double-click on the file, which will have a “.ipd” file extension.
5. Synchronize your Blackberry device with the Desktop Manager, which will restore your contacts.

If you don't have access to a computer, you can access your account information from your BlackBerry with a Wi-Fi connection or data plan. Simply use your BlackBerry browser to follow the preceding steps.
1. Navigate your browser to My.Blackbery.com. Click "Login" near the upper left-hand side of the screen.
2. Click "Forgot password?" and enter the email address associated with your BlackBerry. Click "Continue."
3. Check your email. There should be a message from MyBlackberry.com with a link to reset your password. Click the link, or copy and paste it into your browser.
4. Locate your user name and "Token" (a unique security setting on your BlackBerry) on this screen. Enter a new password in the appropriate boxes, and click "Reset."
5. Click the "Home" link. (You may need to log in again with your new password.) From this site, you now can access and change your Blackberry account information and preferences. For additional questions, click the "+" button next to "Problems with ..." under the "We Recommend" heading on the left-hand side of the screen.