HI Kerin,
Im currenlty able to sync my calendars. given that airbnb wouldn't talk to you I strongly suspect there is a technical glitch occurring. They dont' like to admit to this and never follow up with cusotmers. I'd suggest just checking in every few days - it will probably right itself eventually.
That said, it's not at all unusal for any of the platforms to experience calendar syn glitches - it's not safe to assume they will always work. Because of this, I am more confident about NOT syncing, adn quickly blocking out days on oen platform when I get a booking via another. It's possible I'll get 2 IB's simultaneously, but not really very likely. You're other alternative is to turn off IB on one listing, even if temporarily. I've had CS service close my case without answering several times and remember how isolated and frustrated I felt when it happened. Hope I've been of some help.
Regards