I made that clear to them. So is my money lost forever? This was their final response just now:

”Hi there,


This is Henry from the GDAX escalation team.


The security and integrity of our private keys is of the utmost importance to us. As a result, the specific private keys associated with an address are not available to any single person. Due to the inherent security risks involved with accessing specific private keys, it is not possible for our support team to recover funds sent to a Coinbase wallet in this way.


I understand that this is extremely frustrating, but the unfortunate reality is that maintaining and prioritizing the security of our private keys is our top priority, which means we will not be able to return any digital currency accidentally sent to Coinbase-controlled addresses. I apologize, and wish there was something more we could do.
”