Everything went great very friendly and supportive they seem, interview went for almost 45 mins with 4 professionals, from normal behavior question to learning about each other, their work culture benefit etc as if they were going to hire next day,finally HR said she will get back in a day or two ,but didn't call back or even bother to write back a mail ? disappointed because its not professional to not at least write back even if they don't find me fit or whatever, just write back the usual line ? may be my experience and qualification is far more than any of their current staff ? then why bother interview ? if i don't have problem working on lower level why should they ?

Unless an emergency came up and the company explained this, it's usually a very bad sign if the interviewer is shorter than the scheduled time period. Sometimes initial phone interviews or video interviews are brief, but at minimum, I'd expect them to last for 20-25 minutes.