To manage your Super Suite billing click on the Super Suite icon in the main bar on the left of the screen, and under the Subscription part of the app click Manage subscription at the top right like this:
This will bring up a popup modal screen.
Here you can:
a) Update your plan
b) Cancel your plan
c) Change payment method
d) Update the billing information shown on invoices
e) Download previous invoices
Note: Uninstalling the Super Suite app will not cancel your subscription. This can only be done via 'b' in the image above.