When choosing an exchanger, study user reviews and exchange reserves. When making transactions, remember that in many payment systems they are non-refundable.
To find an exchanger and study their offers, use the BestChange service. This is a free Internet-service intended to help finding electronic currency exchange services with the best exchange rates. Here https://www.bestchange.com/tether-to-dollar-cash.html you can find an exchanger for usdt to usd, as well as for any other cryptocurrency and make your choice