Tech Mahindra Developer interview questions

I applied online and got a mail regarding the interview and the off campus details. (Vardhaman college of engineering) The interview consisted of three rounds. 1st round - online aptitude test for an hour. No negative marking. After the test we were asked to wait in a waiting hall and after an hour results were announced. Cleared the first round. 2nd round - Technical interview. Was asked quetions on databases, java and discussed my resume. Interviewer was quite impressed and said your selected but don't inform others till the results are out. Got selected. 3rd round - HR interview. Basic HR questions. Tell about yourself, family etc. Said keep ready your pan card and passport will issue the offer letter in 15 days. Its been 3 & half years still no information from tech mahindra. There were around 270 students who got selected in that drive with no offer letters till now. Many times we emailed the HR but no response.