If Listing Sync Pro is active, the syncing process will not stop until the billing cycle comes to an end, (even when the product has been canceled).
To stop the sync immediately, you will need to first cancel the product, then click the "force deactivation" button from the kebab menu.
You can turn sync on/off for Google, Facebook, Instagram or X by clicking the sync button under each social site. From here click More > Turn off Syncing.
Please note that since Facebook and Instagram are closely linked, turning sync off for Facebook will also turn off Instagram.