I had this situation in 2014 with Amex and a very large hosting bill from a server provider (non-cloud, it was a typical dedicated host LLC operation, although

I had this situation in 2014 with Amex and a very large hosting bill from a server provider (non-cloud, it was a typical dedicated host LLC operation, although fairly reputable). In my case I had even explicitly instructed them to cancel and they did not. I went back and forth with Amex for about six months. The server provider even forged the date on PDFs to make me look wrong. I don’t remember the exact resolution, I might have partially recovered the money. But it was a nightmare.