Moody's interview questions

HR reached out to me through LinkedIn. I was called for an in person interview three times where I met with 7 different people. I also met with the person I would supervise and overall had a positive experience. I was led to believe that I was the front runner for this position. However, once the interviews were done, there was no response. Upon following up with HR, he kept it vague saying there is an internal candidate for the job. After following up again, no response. Its completely fine not getting a job, but I was annoyed that they didn't have the courtesy to call or at least send a rejection letter. Also I found HR to be rude on the phone and not willing to answer questions. And more importantly, if they already had an internal candidate why did they spend so much time interviewing me??