I think you could send a Bitcoin transaction to your FreeBitco.in account by looking at your Binance transaction history to retrieve your FreeBitco.in deposit address.
Use your own Bitcoin address for this second transaction.
Sign this transaction and maybe it will provide enough confidence for support to remove your 2fa.
Remember that 2fa is for your protection and a website just removing your 2fa actually puts you at risk. So be thankful for their security.
Good luck!
No. Please don't do that. The signed message needs to come from an address previously linked to the account. The reason people use 2fa is that it secures their Freebitcoin account in the event of their email account getting hacked. Without 2fa someone who has control of your email account can reset the password, authorise their login and authorise their withdrawal. They also will have access to all the old emails we sent you confirming your deposits and withdrawals so they'll know all the relevant addresses.
Gotcha, makes sense.