@Peanutstar case has been solved, he paid back the money. Meanwhile, for me, the scammer failed to get the loan due to the address change. I with @Shansan already have multiple successful loans around 150-300$ not only with him but also with @Darkstar_. The sign message is the simplest thing to prove the ownership of your account, however, you need to (Stake) your address first (Unless the hacker compromises your address and is being used for the stake) I can tell the fault is on you.
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None of us want these happening, this business requires both sides. Usually, the lender will ask you to (Sign Message) at the time you ask loan (If this is your first time requesting a loan). Then, If you ask for a loan again with the lender (As long you use the same address you're using from the previous loan) they will not ask you to (Sign-Message) again (Unless) is changed. Well, the hacker asked with his fresh not the same address I was using with Shansan so he declined the request unless he can make some sign message to prove the request was by the real owners who asking loan with a different address.