O2 is one of the biggest network providers in the world. You can trust them will all your telephone, broadband, and device needs. Get and stay connected with O2, visit their online store today! To Redeem, 1. From your O2 mobile, call the O2 top up number 4444. 2. From a landline, call 08456 062 277.https://www.o2.co.uk/termsandconditions/other-products-and-services/free-gift-with-purchase-for-new-o2-drive-customers-terms-and-conditions