Constantia Flexibles interview questions

By far the least professional interview I've ever had. I applied to this position and soon got a quick call invitation which went alright but afterwards I didn't hear back until on a Wednesday a month later where I got asked to come in for an interview the next day in their office at 18.40. As I was in the midst of looking for work, I obviously accepted and replied to the email right away to the same email that sent me the invite. I therefore show up for the interview the day later on time and end up waiting for at least 20 minutes outside of an empty office with no answers to my emails and calls asking if there was anything wrong. This goes on until a very nice worker there asks me if I needed help, and after I explained the situation, he offered to let me in and to look for the person in charge of my interview. This results in the interviewer telling me that they never received my response and presumed I wasn't showing up so the hiring manager wasn't there anymore. I guarantee I sent that email, my only theory is since they sent me the interview request in the same email thread as the first call, those replies might have gotten lost which is something I can understand but is also something that could have been checked and cleared later as they never gave me another email to answer to. But the interviewer still tells me we could have an informal interview which at that point I was desperate enough to do. In this interview I was asked some general questions and nothing really related to the role which was advertised but got asked more questions to see if I would have been capable of working in a chaotic environment. Anyways this interview finishes with them thanking me for coming and telling me that I would still have to go through the first round of live interviews another time, making that whole evening a waste of my time, and I left. Now I hadn't heard a thing back from them until now, a month and a half since that interview. No invitation for an interview and no rejection even after I emailed the same person inquiring for an update which I never got an answer from, until today, almost at the end of April, I get one of those automatic rejection emails. Now, I know that no one is entitled to a response but I find it quite crazy to leave someone with no response even after being emailed asking for updates for more than a month after an interview like that. Kind of sad because I did like the role but ended up with just a lot of stress and very humiliated. I do not give any fault for the possible miscomprehension of the invite getting lost but I do give it to them acting like I never showed up after I gave my time and energy for an interview I had spent days preparing for.