Volvo Group Senior NET Developer interview questions

I sent CV, resume. Quick (in one day) phone interview: 20 mins, probably idiot screening. Quick interview (two days after phone interview): 1 hour. 30 mins tech talk, including what the company does and how, few simple/basic questions about C#/.NET, SOLID principles. 30 mins HR talk. They promised to let me know up to 2 weeks after the interview. I haven't got any reply (4 weeks passed). I even called the HR lady 2 weeks after the interview, and she promised to get back, but no response whatsoever. My opinion: lack of response seems very unprofessional.