yes they are, that's why I had trust in them, but you can clearly see from their article - https://support.coinbase.com/customer/portal/articles/1662379-how-is-coinbase-insured-
"This insurance policy does not cover any losses resulting from the compromise of your individual Coinbase account. It is your responsibility to use a strong password and maintain control of all login credentials you use to access Coinbase ".
STILL, I think support tickets, open case and not giving up is the way to go and a grain of hope. You don't have anything (more) to lose.