Try to recover deleted contacts via iTunes, is designed for data exchange between Apple devices and a personal computer. Each time you connect it automatically sinhroniziruete data on the phone with the computer and saves the backup. Connect your iphone to your computer using the USB cable supplied with the device. The cable has the interface and you can plug it into any USB port on the computer. Wait for the device definition system.
Launch the iTunes application, or wait for its automatic activation, if such a function was previously activated. Just right click the iphone icon in the left part of the window. In the appeared menu choose "Restore from backup". Select the saved copy of the data, which is typically located in the following directory: C:/Users/username/AppData/Roaming/Apple Computer/MobileSync/Backup. Wait until the data recovery process, then you can disconnect the device and check if it lost the contacts.
Synchronize the data on the phone as often as possible in order to prevent their loss. To backup the data on the iphone is through iTunes. After you connect your iphone to computer and run the program, click "Sync" to perform the desired operation. Later versions of iTunes automatically sync when the application starts. You can see this in the description of the current process, which appears in the header of the window.
Install one of the special applications for recovery of contacts from the AppStore via the main menu of the phone. This method is faster because it does not require connecting the phone to the computer.