eBay review: Customer service

I sold an item on Ebay this Summer. The buyer paid right away and then canceled and requested a refund. Granted. Then I relisted the item. Again, someone bought it right away, paid and then canceled and asked for a refund. Again, I refunded. I relisted, and it sold a 3rd time. That buyer also paid and then canceled and wanted a refund. That time, I was not able to refund because my account was locked. I sent a message to Eby and got their generic BOT response. I asked them to refund the buyer and assumed that they did. Then in October, 3 months afer the sale, I get a message from Ebay that the buyer submitted an item not received complaint. I again messaged Ebay, but got the generic BOT response. In December, I got a notice that the buyer submitted a refund through his bank. Ebay then sent me a message today, stating that they ruled in favor of the buyer and were taking funds out of my account plus $20 for a dispute fee! This is outrageous! If they had refunded the buyer back in July, like they were supposed to, then this would not happen. Also, the banned me!