To protect your mobile phone, your giffgaff SIM card is blocked after 3 wrong PIN codes attempts. As soon as you find your PUK code, please type it on your device to unblock it. If you type your PUK code incorrectly for 10 times, your SIM will be permanently blocked so you will need a new SIM card.
If your phone number is inactive during a period of 6 months, your SIM card will be deactivated. If you want to prevent this deactivation, you need to use your phone from time to time.
If you breach the giffgaff Terms and Conditions when using your SIM card (e.g. tethering with an unlimited goodybag) the service may be suspended.
You can obtain a giffgaff PUK code here.