Thanks you for your suggestion. I sent the 10K USDT to the USDC Coinbase Commerce merchant account for the goods and merchant told me that they have mnemonic phase of wallet, There is any possibility to recover from there?
You certainly have a better shot than if you deposited it to a Coinbase account.
Coinbase Commerce is non-custodial. As the merchant suggested, he has access to the recovery phrase. He just can't see the payment through Coinbase Commerce.
The merchant needs to securely import the recovery phrase into a wallet that supports USDT. Then he should be able to see the payment and refund you.
Yes they did with my crypto wallet but when they choose restore with mnemonic phrase there is a thousand of addresses (can only unblock on address at one time) is connected with this mnemonic phrase and there is not such a option that we can search the address I send the payment.