Are you able to cancel the withdrawal? If so I would suggest you do so and convert the USDT to another stablecoin or bitcoin and withdraw that.
Thank you for your answer..
Actually we have an arbitrage software and. Our software catch good signals between hitbtc and other exchange website. So We need to use USDT/BTC trade and withdrawal money from Hitbtc with USDT
This is why arbitrage rarely works across multiple crypto exchanges. There are simply too many occasions where wallets are in maintenance mode, deposits/withdrawals are disabled etc. to consistently make profits. If you can, you should probably try to incorporate that into your arbitrage analysis.
But HitBTC itself is not really a very trustworthy exchange in the first place, due to the large amount of complaints that was present for really the last year or so. In this case your only choice is wait till they fix the problem.
I wouldn't recommend using them, unless you're willing to take up the risk of having to go through potentially draconian KYC/AML measures when withdrawing funds, and deal with the risk of your account being suspended.