Best answer by terrywebbs
Activating a replacement SIM.
If you’ve got a replacement SIM because your old one was lost, stolen, damaged or the wrong size, click on the webchat button below to speak to one of our Live Chat agents. Tell them you’d like to process a SIM swap, and they’ll happily take you through the process.Please have your account details and SIM card number to hand (see ‘Your SIM card number’ below for details on how to find it).
Use the live chat feature in the following link:
https://www.idmobile.co.uk/help-and-advice/contact-us