A decade ago (after my divorce) Capital One accepted my payment in full to settle a debt and then refused to live up to their agreement (which I had in writing) not to adversely impact my credit (and also that of my ex-wife). My ex-wife could have chosen to sue me for damaging her credit, but I was fortunate that she chose not to do so.
It was something that I could overcome without resorting to legal action, so I chose not to sue Capital One to force them to comply with the document they signed. But it was a stressful experience and one that adversely impacted my credit rating until 2016. As an example of some of the crap I had to deal with ... Lowe’s cancelled a credit card on me, and my homeowner’s insurance attempted to raise my rate by $200 (citing my poor credit rating as the reason), but I found a deal with another company for only slightly more than my old premium.
As a result, I will never own another Capital One card. In fact, eight years ago they bought a small bank that I did have a credit card with, and I immediately cancelled that card. Also, 7 years ago, they sent me an application for a new Capital One card, and I wrote “NEVER IN A MILLION YEARS!” across the front of it and sent it back. They appear to have gotten the message, because they’ve never sent me another one.