My full name is John William Russell Anderson, but I only ever go by the name Russ. I simply do not respond to the name John, as I’ve never used it in my life. I realise that in order to verify my account I needed to show my passport (which has my full name on it) but that is in no way how I would ever want to be referred to by customer services. In the in-app chat I get called “John” and I hate it.
To illustrate further, an international example might be the Chinese name order system - for example ex-PM of Singapore, Lee Kuan Yew. His birth name was “Harry Lee Kuan Yew” but if your customer support people had ever called him “Harry” he would’ve been furious (and also his family name is Lee, not Yew)
There’s an excellent document from the W3C on this problem
They do say it’s a hard problem to get right, but PLEASE implement the “What should we call you” field suggestion in that document. This would not only get around my personal issue with being called the wrong name (which is a huge #fail for a company that wants friendlier dialogue with customers) but would also suit anyone in the world who doesn’t go by the “Joe Q. Bloggs” firstname-secondname-surname system that is popular but by no means universal in the UK.