User Activity

The Buyer complains about items he thinks he should have received (but were not in the listing) and after being politely told these items (cables and power supply) were not in the listing, he leaves negative feedback and rants about this "Terrible se...
and after being politely told they (cables and power supply) were not in the listing, he leaves negative feedback and rants about this "Terrible seller". What's the best thing to do? Thanks.