Buy from New Star Diamonds and lose your money

I am very disappointed in New Star Diamonds. I bought several diamonds from Zee and in August 2018 I paid a LOT of money for a flawless marquise diamond. However, the diamond was never delivered despite numerous excuses. I was also promised a refund which never materialised. Losing such a lot of money is unacceptable but apparently it does not bother the owner of this company