I used to buy used things from the Mercari marketplace (similar to eBay), until someone sent the wrong item and I emailed Mercari the same day since their web site wasn't working to open a return request (you have to resolve wrong items within 3 days). Support waited 3 days to respond and told me I was outside the window so they couldn't refund me and that I should have done it sooner. I did a chargeback and they were angry and told me to reverse it. They then banned my household for life.

And then there's PayPal who refused to refund from a clear scam for almost $5K, even after I left a BBB complaint. Credit card chargeback saved the day, again. They didn't ban me, oddly.

I guess this is an endorsement of using a credit card.