EPAM Systems interview questions

Two phone interviews. One HR and one technical. Interviewers were from Belarus. Technical interview was more than 1.5 hours long and pretty easy interview. Asked simple queries involving OLAP functions , questions around SDLC , UML diagrams and questions around my resume. ETL design methodologies , data warehouse concepts. Few days after the interview I got an email from the HR that I have qualified and they want to move forward with the next steps and made me sign the NDA . But the next interview never happened. I kept following up with them for two months but never got a reply. I texted the recruiter via Linkedin as well (thats how she had reached me ) demanding an answer and their decision , I never got any reply. Now I feel happy that I didn't join them because if HRs act like this before joining the organization , then I wonder how will they behave after you join them. I still don't understand who gave them the authority to waste my time. If they can give any justification then I can make peace with them.