Storecast interview questions

The interview process was divided into 3 steps first one was an HR and technical screening via Skype, I passed it with a good feedback from the interviewers, then they send me a task to do, I did it and they send me a good feedback about it but after about a month, after that they invited me to visit their office in Berlin, the day was good, we went to lunch and after that I attended a scrum meeting with them, and we had a good talk about their app code and my task, after that I had a private meeting with the HR manager and mobile development team leader we agreed on the salary and everything else, after I came back from Berlin I found them wanted to have another screening call and task for about 1 hour with live coding, then they sent me rejection mail, I asked them about the feedback and why that happened the didn't reply yet.