I was fighting with them over the same issue for several months in order to get access to GDAX. I finally gave up and used competitors services. I sent pictures (via their webcam tool) of drivers license, passport and green card, and they wouldn't accept any of them. Emails to support detailing my situation were always answered with useless canned responses. I like the simplicity of Coinbase, but their authentication procedure fails when dealing with people who reside outside their country of origin.