1HaLHSjTdCr3buSQWrGnYK7QSzPwaoyKYi = My BTC deposit address on Poloniex which I've used since 2015, I still have access to it but how can I sign a message to my Polo wallet?
You can't able to given a sign message with that. But you still have best way, were for those lender want to fill your ask will be filling to address staked above.
I can fill your ask, TBH.
But I guessing you want to intend of account like a sold.
I see, I am happy for the above address 1HaLHSjTdCr3buSQWrGnYK7QSzPwaoyKY (My polo address) to be used for the loan deposit.