Engagement ring sales scammed

I purchased a 1.51 carat VVS2 / D color engagement ring on December 2. Original price was $ 26,000 I received it on December 4.It turned out that the attached GIA certificate was a VS2 / D color grade diamondThis is a lower grade diamond. The difference is about $ 5,000~ $ 6,000I immediately called their customer service center and the service staff only told me that if you don’t like it, you can get it back for a refund.No sincere apology, no reasonable explanation, and no supervisor informing me of the solutionSo far, they have not given me a satisfactory answer, and company executives have not called me. Poor service attitude