Since this was an *obvious* mistake in the first place (probably an automatic computer calculation), I suggest that one should first contact the company about an issue before denigrating it on an internet forum.
He denigrated nobody. The only denigration seems to be you denigrating the author. He only expressed his dismay and frustration. HRO is not above people expressing dismay at this, a wrongful situation in any public forum. I support the author. After that incident, if no forthcoming sensible and plausible explanation from HRO, if I were the author, I'd never do business with them again. And I'm a repeat customer of HRO.
Good. You support the author. I'll still support HRO. When he contacted HRO (something he should have done before posting a complaint on the forum), everything was resolved and he's a very happy camper. Apparently, there was a "sensible and plausible" explanation.
I was in retail sales for over 40 years, and I had my fill of people that jumped down a salesman's throat before a sensible explanation and easy resolution to a problem/situation was given.