IBM Senior Software Engineer Java Developer interview questions

All were virtual rounds due to pandemic. At first the HR called for details and then for online test for which I received the link same day, multiple links, I cleared it and then next day called for scheduling the interview and when I gave my suitable timings it was scheduled accordingly, but two times no one joined the call to take interview. The third time they called randomly and asked to give interview in half an hour and no one joined again. Then it was scheduled after one week for which I got feedback as cleared and they will schedule next round. But that never happened

They took one online test which was easy then they called after a month, and scheduled interview and told me that it would be an hour long tech discussion anytime between 12 to 2 pm and then they made me invest 5 hours for 1 round and they called again to schedule another round at 5 pm which i they conducted at 9 pm then they asked for my documents after that if i had any offers ,i provided all to them. For the next week they made me submit many other details and cognitive ability test and all. So at this point i thought i am definitely in. Then i didn't hear from them for a month. So i called afterwards and then there is this guy who told me that i was rejected in the 2nd round only due to some negative feedback. And i can make sure all of the rounds were easy and i didn't even missed answering a single question. Still i got rejected. Felt bad for wasting my time. My suggestion to IBM is that please make sure you don't waste time of candidates, i know you are a big firm and but these small things makes a big statement qbout your management.