You can revoke the access of a platform at any time from the Settings > Team and Security > Installed Apps area of your Dashboard.
Note: if the third-party platform is creating Subscriptions for you, we strongly recommend first discussing Subscription migration options with the platform before disconnecting. Disconnecting your account from a third party platform while there are active Subscriptions can have implications depending on how the Subscription was created.
You may be restricted from revoking platform access if you signed up with a Connect platform that has platform controls for connected accounts. Reach out to the platform to initiate the disconnection process for you.