Amazon Account Blocked - Incompetent Customer Service

Hello,

Last Monday (11/19/2018), I made a purchase on Amazon.fr; so far, so good, but a few minutes later, I receive an email informing me that my order is "on hold" and that my account is locked because Amazon was unable to verify my banking details.
The email asks me to send a bank statement showing my first and last name along with the last four digits of my credit card to unlock my account.
However, there is no indication in the email of where I should send these documents. I check, and indeed my account is blocked, but I still have access to one feature: my order history (which is empty by the way, even though I just placed an order).
After checking, the email is indeed an official email from Amazon.fr, so I try to respond by sending the requested documents (I only show the strictly necessary, but the requested information is clearly visible). However, this email address does not receive messages (I was somewhat expecting that). I inquire on forums and apparently, I am not the only one whose account was blocked for no apparent reason following a purchase. However, all other people had received a fax number to send the documents or a postal address based in London (What customer service still uses faxes or letters to communicate, especially for such important and urgent requests?).
Before attempting to send a fax, I decide to contact customer service from the website...
You can only contact customer service if you are logged into your account (mine is locked); however, I manage to find a phone number, so I call, and I am made to understand that customer service cannot do anything for locked accounts, I need to contact the "Account Specialists" (the guys who work by fax). I’ll skip the details, but I also tried to create a new account to send them emails (which either went unanswered or received an automatic response that did not progress anything). It has now been 2 days since the account was locked and I receive an email stating that my order (which was supposed to be on hold/canceled) will be delayed, this email follows the first email stating that my account is locked because the payment did not go through (so I deduce that they are trying to charge me repeatedly and ship my order even though I no longer have access to my account).
I finally find a way to send a fax to the "Account Specialists" containing a summary of my situation as well as the requested documents, and their response is incomprehensible. They wish to contact my bank to verify the validity of my banking details when I have already provided all the requested documents in the emails (official documents coming from my bank, precisely). I reply that my bank does not engage in such practices. They send me exactly the same email back. This is complete bullshit. I am now at two calls to customer service, 3 faxes sent, and a dozen emails, and I see no end in sight; between the vague automated emails where nothing is understood, the customer service which has no control over anything (I do not know whether to laugh or cry, but the customer service representatives speak like robots, repeating only pre-written phrases and following a script, talk about a customer-oriented service), the unanswered emails, and the only ones who can help me work by fax and want to contact my bank when I have provided all the evidence. In the meantime, my order of €710 is going in circles, and I can neither cancel it since I no longer have access to my account nor shop elsewhere for fear of being charged twice €700.
In short, I am quite desperate and especially very disappointed with Amazon, a large company with so many resources that offers a pathetic service if your account is locked (I understand that this comes from the intention to secure my data, but it has become ridiculous since all my documents are in order as they requested).
Has anyone had a similar experience and could help me either delete my account, permanently cancel my order, or simply recover my account?

Thank you for reading my long message, hoping to find a solution.