ROLLER Software Engineer interview questions

Weird and unfair experience at and after the very first interview with a specific Senior Talent Acquisition Manager. The interview meeting invite email clearly mentioned (in bold letters) that as part of this interview - "We will also be going through some technical questions that will give us an understanding of your knowledge with C# .Net, Web & Database topics" - for which I had prepared as well. But during the actual Interview, there were just high level talks, very few casual questions on experience and NO technical questions asked at all, just a "Thank you for talking with us" and said that they would mail me the next steps in a couple of days. Then a couple of days later, received a Rejection email. I mean why waste candidate's time and efforts if you are not serious about giving them a fair chance to let them move to next rounds, and just filling your timesheets. Unprofessional and fishy to say the least.