What exactly do you want to pay? Your account does not currently own any upgrades on WordPress.com.
I can see you used to own a Premium Plan with us, but that plan has already been removed from your account. If you want a new plan, you can just upgrade again from My Site ->Plans.
I also see your site has a domain mapping upgrade that belongs to a different account, tucsonea. You will need to be logged in as that account to renew that upgrade.
However, if you buy a new Premium Plan, I strongly recommend that you ask tucsonea to transfer that domain mapping to your account, as then you’ll be able to renew it for free – if you own a plan you don’t need to pay separately for domain mapping on a site. But if the plan and the domain mapping belongs to different accounts, the owner of the domain mapping will have to pay for it separately.
tucsonea can just comment here to confirm, then we can move the mapping over to your account for you.