I did a first interview with a short technical test in a platform. Then I was invited to a second one, that was an assessment center, lasted 4 hours and it was quite intense. Then they took 1month and a half until they told me I was not selected. Meanwhile I sent them an email asking them for feedback after 3 weeks passed, which they ignored. I knew that I had not done very well in the interview, but after devoting them so much of my time, I was expecting at least for them to answer my mails.