Tower Research Capital Development Tools Engineer interview questions

First I was given a HackerRank test to solve within two weeks. It had questions on shell commands, python programming, some MCQs, debugging a python code, writing small shell script, debugging an ELF, networking, etc.. After this, I had two telephonic rounds, over a period of one month or more. Both began with a discussion of my resume, profile and work experience. The first one had questions on solving a graph/matrix problem in Python, Git, Docker, their working and a bit of their internals/functioning. The second one began with a Python debugging question that I hadn't attempted in my HackerRank test. I solved it in the interview and then the interviewer moved on to other questions on ELF/Binary files, an API to put and get objects (this was very vague, confusing and funny - a technical discussion, I never imagined having with someone over the phone. Maybe they are too afraid to let people in their office.), etc. Overall, in my experience, the organization and people seem to be quite full of themselves. They had to test me thrice before they could consider me eligible for further testing on their premises. The second interviewer wasn't on time and I had to mail the recruiter to inform that I had become available for interview. Also, both of the interviewers were stretched to more than an hour when originally they were scheduled and supposed to be only for an hour. You know, they won't let you interview for that one hour on weekends or some morning/evening time but still they don't care at all about your time in the interview process. I wonder if it's alright to remind the interviewers when the time is up. Even after spending so much time and going through all this, they didn't even care to drop me a closure email about my rejection or anything. It's been so many days now. I wonder about the revenue they must be having to afford such an attitude.