Most people will be able to update or change their payment details by following the instructions in the video below (if you don't see what we describe in this video keep reading).
Watch the video below:
Log in to your account on Co-Kinetic (make sure it is the same account that holds your subscription)
Click on the down arrow next to your name in the top right hand corner of the screen once you're logged in, and click Your Profile
Click on the Payment Details tab and add your new card details
VERY IMPORTANT: If there is more than one card stored, make sure to click the 3 vertical dots and choose the Set As Default (you should see a tag saying Default appear next to your card of choice).