He's right, the only way to get the PUK code is to ring up the network but the sim card has to be registered in your name and address otherwise they won't give it to you. You can still use the phone with another sim card though.
the PUK code is unique to each SIM and is not assigned a default number. The Personal Unblocking code is the last way to clear a PIN block. A PIN block occurs when you enter the PIN wrong 3 times in a row. The PUK code is stored on the SIM and is checked when you enter it manually after getting it from your provider.