Infograins Software Solutions Sr. Android Developer interview questions

First they call for the interview there are 2 round of interview it was good, 1st round is technical interview and 2nd was machine test. After clearing the machine test they call me for final discussion. They give me offer and give me 3 days to confirm and I confirm that I will join and go for joining and then they said we can't provide the salary as much I expected. I did not understand.