It can be frustrating when your phone's asking you for a 'PUK code' and you don't know where to find it.
Our guide shows you how to get the 'Personal Unlocking Key' (PUK) that you need to get up and running again.
Check the card carrier that came in the pack - that's the credit-card sized piece of plastic you pushed the SIM card out of. The PUK Code is an eight digit number, and is usually printed on the carrier.
The PUK code is tied to the SIM card, so you have to get it from your mobile network provider. We've listed contact information for the main UK mobile networks below.
When you've got the code, follow the instructions on the phone. If it doesn't work, contact your mobile network because entering the wrong PUK ten times will block the SIM card.
You might be asked to set a PIN when you've finished. If you do, make a note of it, because entering it wrong three times will, annoyingly, make you need the PUK again.
Hopefully that's your phone working again, but if you need more help, you can get in touch with a Team Knowhow Expert here.