If you have entered the PUK code incorrectly into your phone 7 times, the SIM card will be disabled and you will need to:
Grab a blank SIM for $4 from a The Warehouse Store or grab one online here. These have no number or credit against them.
Once you have your blank SIM give us a call on 0800 284 800 with the SIM card to arrange moving your number and any remaining credit over - you will still keep your original number and any remaining credit you had on it. It should only take 5 minutes.