This is what I got from T-mobile
Thanks for placing an order online with T-Mobile.
We're really sorry but there was an error on the T-Mobile website and the price of the plan you ordered was incorrect. The price of your chosen plan is actually £10.21 a month, so we are unable to proceed with your offer to pay £0.00 a month instead.
To say sorry and to make sure you still get the great value plan you're looking for, we are happy to offer you a discounted price of £7.71 a month for 12 months instead.
If you are interested in accepting this offer, please call us on 0800 956 5038 and choose option 3 within the next 5 days with the following order reference number - 2835403. If we don't hear from you within 7 days from your original date of ordering, then we'll assume you no longer wish to keep the service and we'll cancel your account.
We're available between 8am and 9pm, Monday to Friday and 8am to 8pm on a Saturday. If you would like to check our legal stuff for online orders click here.
We look forward to hearing from you soon.
Kind regards,
T-Mobile