Infosys Flutter Developer interview questions

1 - HR screening call 2 - online interview where flutter questions was asked with DSA 3 - F2F interview email 1 day before i received i traveled overnight 500 km to reach the interview destination and interview was also in morning.. still everything went well They told me to wait in one room 4 - After waiting for 20 minutes hr came took me to her cabin basic talk and salary discussion happened. HR said "Congratulations, You will receive offer within 2 weeks" Very next day Background verification email i got i completed that everything was okay Then randomly i got rejection email without any explanation why leaving me devastated and frustrated