Calendar synch with Airbnb is mixed up but I can't remove it

I am having 4 fragments of an Airbnb iCal connection, two having status 'activating' and two import needed..and all highlighting that I need to complete the setup.

When I complete one setup only one entry remains and i can not remove any of them. Even if i try to remove I again seeing the 4 fragments as in the beginning and everyting starts again.

I would like to remove all of them and to start over. This does not work. I can't remove it when it is in status 'complete setup'.