Thank you for getting back to us here in the Community. I want to assist you with your concern about disconnecting an app in QuickBooks Online.
Connected third-party applications should show in the MyApps section within QuickBooks Online. If it doesn't show the Square app, the automatic syncing of transactions into the account will discontinue.
I've checked here if there's an ongoing issue going on with the disconnecting application, but haven't found one. You can try switching to a different supported browser to check if the problem is browser or system related.
If it continues to import the data into the system, I recommend reaching out to our Support Specialists this time. They have the tools to check accounts and further investigate why this is happening on your end.
Here's how you can reach them:
Log into your QuickBooks account.
Click the Help option in the upper-right corner.
Click Contact us.
In case you need to reach out to our support in the future, you can bookmark this link on your current browser: