Talked with HR on the phone and then I got invited to personal interview. Over there I talked to HR again and did short test on React

The interview process was comfortable and interesting. No signs of trouble. They told that they are ready to hire me. We signed a contract, resolve all paper stuff and in a few days I had to start. Also I should have passed the test on reliability. HR told me that the test was alright and they want to schedule another one - it happens quite a lot, as they told me. A few days later they delayed the start by a week. And then HR called me and said that I failed the reliability test. And for this reason, they will not work with me, although we have already signed a contract. In the reliability test, I mistakenly gave the wrong answer, I indicated this mistake in the comments. During the second test, I told the interviewer that I answered by mistake, he said that I should not worry about it, it happens to everyone, everything is fine. And then they just dumped me. Terrible approach to business. If your plans have changed, just say so, why lie?