There have been many discussions about reporting Ebay sellers who sell fakes or violate intellectual property rights. People often complain that nothing is done about those reports.

The proper method of reporting infringements or fakes is found here: https://pages.ebay.com/seller-center/listing-and-marketing/verified-rights-owner-program.html#m17-1-tb2

Keep in mind that some reports have to be made by the copyright holder (for example, the Chip Guide rather than a concerned bystander). The Ebay page is unclear whether fakes and replicas have to be reported by a particular person (such as rights owners), so some claims may be rejected for that reason.