BASF Technology Analyst interview questions

I applied for this position in July. They called me in September to do the first interview. I did the 1st interview with 2 managers and it went well, they called me the day after saying "your interview went really well" and sheduled me for a 2nd interview. Did the 2nd interview with 2 peers, it went fine, they asked me the same questions as the 1st one. Called me the day after for scheduling the 3rd one. Did the 3rd one with other 2 managers, went fine. They said "we will get back to you in 1-2 weeks". 3 weeks pass, I send an email to HR, no response. I send an email the week after, so in total 4 weeks after my 3rd interview, they send me an automated message with the rejection. Really? An automated message with no explanation? They just wasted my time and gave me false expectations. Unprofessional that I had to send 2 emails to know that I was rejected after 1 month of leaving me hanging. The managers were all nice people though.