Hi @Anonymous User
Firstly whilst logged in on here go to My Account > Settings & Pins and add a payment pin to your account which should avoid this happening in the future.
Then pop over to live chat and explain to them what's happened and ask them for a refund for the accidental pass you purchased.
To reach live chat open the link below and click on the small green down arrow directly underneath How to Get in Touch.
https://help.nowtv.com/gb/get-in-touch/now-tv-passes/now-tv-passes-prices
