Extreme Networks Angular Developer interview questions

Total 3 rounds : all 3 technical and last round includes discussion with manager. I cleared all the rounds and in the last round, I got a feedback as I am through with the interviewsand we discussed about salary and date of joining. After 2hrs I will get a message from HR, that I am not selected and the reason was, my skills not matching with their requirment. I was wondering about this! then why they conducted 3 technical rounds and they provided 2 different feedbacks. I had a worst interview experiance with this company.