Robert Bosch Senior Python Developer interview questions

I had three round of interview at Robert Bosch.First round was based technical discussion and second round Group Manager ans third round was hr and salary discussion.Technical interview was of medium difficulty level. It was nice. Group manager round was of half an hour round and it was ok. I gave hr found and hr told that she is fine with my expected salary .They also mailed me about credential of first steps and I shared details .I was waiting for offer letter but hr ensured it will be relased in 3 to 4 working days.But when I called hr after 3 days they told your offer is kept on hold. Its waste of time for me and they should reject the candidate at a very first place itself.