Disney+ Plus free for 3 months on O2 - text "DISNEY3" to 21500 (Account specific)

SUBSCRIPTION TERMS

Subscription and Auto-Renewal. Your subscription to the Disney+ Service includes enrolment into an ongoing/recurring payment plan. Your subscription will automatically renew at the end of the disclosed billing period, unless cancelled in accordance with the instructions for cancellation below. Payment will be charged to your chosen payment method at confirmation of purchase and at the start of every new billing period, unless cancelled. We reserve the right to change our pricing and, in the event of a price change, we will notify you thirty (30) days in advance of the change by sending an email to the email address you have registered for your account. If you do not wish to accept a price change, you may cancel your subscription in accordance with the instructions included in that email and below. If you do not cancel your subscription after the price change takes effect and prior to the start of your new subscription period, your subscription will be renewed at the price in effect at the time of the renewal, without any additional action by you, and you authorize us to charge your payment method for these amounts. You are responsible for all third-party Internet access charges in connection with your use of the Disney+ Service. Please check with your Internet provider for information on possible Internet data usage charges.

Free Trials. Your Disney+ Service subscription may begin with a free trial. Availability of a free trial is not guaranteed and, if one is available, is only available to those who have not previously used one for the Disney+ Service. Your first payment will be charged to your chosen payment method immediately following the free trial, unless cancelled in accordance with the instructions for cancellation below. You can cancel your subscription at any time before the end of your free trial. We provide notice of the terms of the free trial at the time you register but you will not receive a separate notice that your free trial is about to end or has ended, or that your paid subscription has begun.

Cancellation and Refund Policy. You can cancel your subscription at any time before the end of the current billing period or free trial. Cancellation will take effect at the end of the current billing period or free trial. To cancel your Disney+ subscription, navigate to disneyplus.com/acc…ion (http://www.disneyplus.com/account/cancel-subscription) and click "Complete Cancellation." If you subscribed via a third party (e.g. an app store such as iTunes, Google Play, Amazon Store, or Roku), please visit our Help Centre for instructions on how to cancel. Cancellation will only take effect at the end of your current billing period (or end of your free trial), and you will still be able to access Disney+ until then. We do not refund or credit for partially used billing periods. You have a statutory right to withdraw within 14 days of signing up to the Disney+ Service. However, you acknowledge that when you signed up to the Disney+ Service you agreed to the immediate download of digital content and that if you access any digital content, you lose our right to withdraw from the Disne + Service.

Seems like you must wait for your Extra to expire (get an email from Disney to say your paid subscription has resumed/started or an email from O2 to say your Extra has ended) and then try sending the Text and it should renew and add an additional 3 months.