I had a dude on Reverb try to scam me out of a guitar I sold him nearly a year ago. It was a PRS Clint Lowery sig. He paid my full asking price, which should have been a red flag considering this was right when everything started getting locked down and everyone was supposedly being tight with money. But I digress. He messaged me saying he had issues with it being 'unplayable', pickups were weak (they were Fluence Moderns with extra new battery sent with it) and the low E string was buzzing really bad at the higher frets. Asked him to show me what he was talking about, as I was stumped because it was in perfect playing order when I sold it to him. He sent a vid showing the buzzing, then sent a pic of the low E side of the bridge screwed all the way down. He said he tried adjusting the action but that didn't work and he just wanted a full refund for a defective item. I pointed out that a simple bridge adjustment would easily fix the 'issue'. So I immediately started a dispute with Reverb because A) I know I didn't sell it like that B) He admitted to tinkering with it, and C) it is an easy fix that anyone buying a used guitar may have to do anyway upon delivery after shipping across the country. Reverb was on his side 100% and I still refused to give a full refund because he admitted he messed with it but I couldn't prove he was the one that did the 'damage'. So I messaged the guy, accused him of having buyer's remorse and dishonestly manipulating the guitar/fraud, and I even offered to take it back and 'fix it' for him, as well as pay for shipping back to me, and shipping back to him. He changed his tune pretty quick after that message, somewhat. So I get the guitar back, do a quick bridge adjustment and it's as good as it originally was when I first sent it, took pics of it, took a vid of it playing, and he accepted the guitar back again. Ultimately he left a good review as I did for him, but waited until he closed the dispute himself, but man that one really pissed me off. In the end I figured it was worth taking a $200 hit for shipping to 'make it right' than to lose $750 altogether.
And that, folks, was the last time I did anything on Reverb. It was that transaction that I realized the seller has zero power regardless of evidence.