The platform pretty much promotes selling fake products

I bought AirPods Pro 2 from user35265, and the item I received was not Brand New as listed. I was disappointed but tried to give the seller the benefit of the doubt, so I didn't make a big fuss about it. I ordered it for my dad so he could use it as a hearing aid. I paired it with my iPhone but didn't see the hearing test, so I tried to update the firmware as described on the Apple support page, but unfortunately, the firmware did not update. I made an appointment with an Apple Genius Bar, and they tried to diagnose the issue. The technician came back and told me that the item is fake and not authentic. She mentioned that the serial number on the case has been used many times, i.e., many customers have come in with AirPods having the same serial number. Mercari's auto-review policy after 3 days and their rule against allowing buyers to modify reviews essentially promotes sellers selling fake items without consequences.
From now on, using eBay instead.