If your net profit during 30 days challenge period is more than Rs.1000, then you are eligible for refund of brokerage during this period and certificate.
If net profit is less than Rs.1000, then you are eligible only for Certificate.
For more details, pl. refer -
https://support.fyers.in/portal/en/kb/articles/what-is-the-fyers-30-day-challenge6
https://www.fyers.in/notice-board?p=3186
Pl. Note : I am not from Fyers Team.