1

Go to Organization Settings

In the Polar dashboard sidebar, click on Settings. You can also go directly to:
https://polar.sh/dashboard/${org_slug}/settings
Scroll down to Subscriptions section.
2

Toggle Allow price changes

Toggle OFF Allow price changes to prevent customers from upgrading or downgrading their subscriptions from the customer portal.
3

Save the changes

Click Save in the Subscriptions section to save the changed settings.