Are you somewhat came from US? Bitfinex is somewhat playing this crypto hostage game for a while now, there are lots of users who experienced such this and can't read any of those got resolve.
Better to get in touch with them regarding this and try to make a way on how you can get/make this proof of funding docs.
I'm not in the USA.
If you have had coin sitting in your bitfinex account for 4-5 years, they probably want to be sure your account is not hacked. I would encourage you to work with their support to gain access to the coin you want to withdraw. If you can sign a message from an address you previously deposited from, it should increase their confidence that you are in fact the 'real' owner of the account, and not someone who successfully hacked the account.
I've been dealing with this for 1 month. If I were a hacker, wouldn't the owner of the account wake up in 1 month?
* A detailed explanation of the sources of all funds deposited to Bitfinex. You will have to show how you used fiat funds to acquire cryptocurrency
* A proof of source of funds confirming how the deposited funds were originally acquired. You will have to show employment documents or income statements showing your source of wealth to acquire cryptocurrency
* International Passport (scan and "selfie) in high resolution
* National ID / Driving License (scan and "selfie) in high resolution
* Proof of Address (government issued or utility company)
You are free to seek independent legal opinion and take whatever action you feel is adequate at this time, as our position will not change.
If you continue to create new helpdesk support tickets, without responding adequately to our inquiry, we may be forced to restrict access to your account until such times the documents requested are provided.
Now they want these. Something is missing here. My grandfather's selfie. Their purpose is to extortion crypto money. Stay away.