SHEIN Order Cancelled but Refund Still Missing on Visa Card

I placed an order with SHEIN from New York and paid approximately $400 using my Visa card. On the 22nd, SHEIN cancelled my order and indicated that a refund had been issued, but to this day I have not received any refund in my account. I tried to contact SHEIN customer service about this issue but I could not get through or receive any assistance. I am currently without the products I ordered and without the money I paid, which is very upsetting. I request that SHEIN either promptly send my original order or, if that is not possible, immediately refund the full amount of $400 to my Visa card and confirm this in writing.