then why does Binance support claim the merchant - justanotherpanel.com has successfully received the coins? Even when it was USDT to USDC address.
The transaction went ok and confirmed and this mistake usually happens if the sender hasn't doubled check the transaction. As you know, crypto transactions are irreversible that's why Binance can't do anything with it.
I've told you to contact the justanotherpanel.com which you have sent the USDT. I don't know how they do it but if that website tells you that you can't claim it anymore, there's nothing you can do.