Fanxiang S770 SSD 2 TB. FAKE SSD. LESS THAN 4 GB/s ON PCIe 3.0

We tested this Fanxiang S770 NVMe SSD with 2 terabytes of storage in a PCEe 3.0 computer with a theoretical capacity of 16 GB/s. The results speak for themselves. The hard drive does not reach the speeds it should give. It does not even reach 4GB/s. The manufacturer refuses to return the product even though they clearly stated that the return was free of charge and without obligation. What do you guys think, could it be considered a scam, or just a lousy seller and a lousy product?