Here's the story: Israeli runner Itai Spiegel was being coached by Matt Fox. He ran a 2:05 800 and let Matt know to get some feedback. Matt proceeded to take 50 hours to respond and he used ChatGPT to write a generic congratulatory response, and didn't even say Itais name (it said congratulations Matt!). Itai sends an email back pretty disappointed with the level of support he's getting and asks to cancel. Instead of trying to course correct or apologize or open some dialog, he shoots back a bunch horrible comments (see link). Beatie Deutsch and Alli Felsenthal posted on their stories about this situation to raise awareness of this guy being a complete @$$ and he proceeded to fire back with more disgusting comments. As I am typing this out, despite being blocked by Beatie, he is going through his other accounts to continue to threaten and harass her.
My $0.02: I could never imagine responding to a client this unprofessionally. Anybody that is being "coached" by him or subscribed to his website should seriously consider cancelling.