Did you try to call their customer service? I ran into the exact same situation with Amazon once. I was trying to sign up a free trial on audible.com, and my years old account had been locked immediately. To make it worse, my AWS services is on the same account, and I was locked out from the AWS console to manage my servers. At the same time, ironically, I still got monthly bills from AWS which I can't even pay. I tried several times to provide as much information as I can on that stupid login page but with no reveal (my bank doesn't send billing statements too, it's all on their app). Finally, I found Amazon's customer service phone number on a purposely hard to find webpage, the woman on the phone was nice and said she will try to contact the relevant person for me. After hung up the phone, I made a final attempt by uploaded a photo of my credit card. The next day, my account was unlocked. I don't know which method finally worked, but it worth a try.