Wipro Senior Java Developer interview questions

One technical round HR round I have cleared both technical and HR round on the same day.We have discussed my salary expectation. After one and a half month suddenly they called and informed me that they will release my offer letter with an amount which is very less than the amount we have discussed in HR round.why they are conducting interview when they will not be able to provide mutually agreed salary? Its a total waste of time.Now if this is the process before onbaording i am thinking what will be the process after onboarding. Shame on you WIPRO.