KPIT hired us in our college at 4.5 lpa and told us after 3 years they will pay 17 lpa they lying or not?

Until it's written in offer letter it's not official

This is news to me. No company I know tells upfront about what the compensation would be after 3 years. Did you get that in writing?

Lying

Forget about 17lpa, 1st of all they will not onboard freshers they will make you wait for 1-1.5 yr after your graduation

Tell them to hire you after 3 years only then