How to delete a orphaned linked service in google assistant

Hope this is the right section. I followed this tutorial (Google Assistant - Home Assistant) to link my HA to google Assistant (several times as after a while it does not sync anymore). One time i made a mistake and linked a deleted one in google home app. In the google home app it does not show as a linked service, but when i sync my google home the assistant says me it can only be synced by the owner (and with a few voice google assistant commands it says the service cannot be reached).
Can anyone help how to get rid of such an orphaned app/service, in the google home app it is not possible because there it seems not be linked?

Thanks Mike