I use these guys all the time to buy my cryptos. Sometimes when you transfer your coins to your wallet off the exchange, they don’t go right away, so you have to send them an email to get things moving. But overall they are good.
I withdrew some coins from Kucoin to my external wallet. It shows successful in my Kucoin account, but it has not arrived in my external wallet after 3 days. I have written to support but they have not responded.