First logout if you were logged in clicking on the white figure in the right upper corner and choose "logout" at the bottom.
Then please open this website www.clipmyhorse.tv/en_GB/register
Please pick the Premium Membership listed in the middle and click "Choose Plan".
Add the email address you are using for your Badminton Season Pass, It will say your email is in use then please press "Try to login".
Please check your billing address and your payment method, both need to be valid. Edit it accordingly if needed.
Then also add your discount code here and click on "check code" and tick the lowest box.
Please then logout and in again to make sure your membership logs are updated to a premium account.
You should be all setup now with a fresh premium membership. Please contact support on supprt@clipmyhorse.tv to make sure your Badminton season pass is cancelled and won't auto renew next year as Badminton is included in your premium membership.