If you no longer use Quickbooks Online, you can disconnect it from your ServiceBridge account.
Login to ServiceBridge and go to Company settings.
Under your Company settings, go to Quickbooks section and click Disconnect from QuickBooks.
In case you accidentally disconnected your Quickbooks, refer to How to Connect to QuickBooks Online.
Also, please contact firstname.lastname@example.org if you need to switch to a different Quickbooks Online account.