At some point, I had a complaint, refunded the customer completely, and they outright banned my account and held my money for 90 days (I got all of my money back after the 90 days). It completely wiped my business out and I never looked back.
I was banned to the point where if another seller was associated why my account at all, they were also banned. All of my calls went nowhere and I was pushed to automated responses.
12+ years later and I have my seller account back. Not like I'm ever going to sell anything on Amazon again.