We essentially could not figure out how to contact anyone at Google Flights to clear up the situation or achieve any form of redress.
> Note: All bookings are made with the relevant airline or online travel agency.
Something like this had happened to me often enough that I no longer purchase anything through an intermediary when traveling. Flights, directly through the airline. Hotels, directly through the hotel. Theme park, directly through the park. Is it convenient to make reservations and/or pay in person on-site? On-site it is.
The occasional discounts just aren't worth the clusterfsck it becomes when there's any kind of misunderstanding or miscommunication.