MX Account Manager interview questions

The interview process entails a recruiter screen, an interview with the hiring manager, two panel interviews, and one final interview with someone senior within the firm. The interview process was smooth until the final stage, where after the final interview, I had zero communications from MX for almost a month, despite them saying I was a finalist for the position. Multiple email nudges for an update were answered with silence. Finally, I called the firm, who then told me that they had decided to move forward with other candidates. I never received a formal notification from MX regarding my application, after five interviews and 4.5 hours of talking to a wide range of people around the firm. It's just bad form to not tell someone the result of their application, especially this deep into the process.