What it is
On this article you can see how to disconnect Hubspot and Bloobirds.
Bear in mind that to be successful, you have to remove the integration in Bloobirds and also in Hubspot.
How it works
First, enter your Hubspot, go to your connected apps and disconnect Bloobirds by clicking on More and then Uninstall.
Confirm you want to uninstall the Bloobirds app by typing "uninstall" and then clicking on Uninstall.
Finally, to remove the integration also on the Bloobirds app, navigate to the tab Sync settings and then Bloobirds -> Hubspot.
When ready, click on DISCONNECT HUBSPOT.
A warning will show up, click on CONFIRM.
You need to remove the integration of HubSpot and on Bloobirds. If you forget to remove the integration on the Hubspot app, you will still be getting updates from Hubspot.