Infogain Senior Plsql Developer interview questions

There were 4 rounds of interview, two technical, one managerial round followed by HR round. Interview experience was good and HR communicated she will send offer letter and initiated the background process. I submitted all documents and HR asked to join immediately following Monday. They told they will release offer letter and till now no news. It's been a month now. I have been following up with consultancies and Infogain HR and they are now saying they will get back. What I expect is a formal closure telling what is blocking. Unnecessarily waste of interview time and highly unprofessional.