Nandan Petrochem interview questions

Questions were like any other normal brand management interview and I was quite happy to meet the hiring manager. He was kind and seemed like someone I would definitely learn from. It started off great but then for a whole month HR kept avoiding me after being shortlisted for the next round. Kept saying yes will call you this week. Made me do some presentation as well but never gave a single feedback and just ghosted me. I did multiple follow ups but nothing. Quite unhappy with the unprofessionalism. A single sentence or a just the word NO is enough to let a candidate know they are no longer being considered. Why waste weeks and weeks and leave the candidate hanging?