Sasta Safar — No full refund on flight cancellation

Website:

www.sastasafar.com/flight-deal?utm_source=ggl_ssf_pmx&gad_source=1

I booked SpiceJet flight from Gorakhpur to Mumbai via Sasta Safar. Ticket cost was 14, 155 INR. On flight cancellation by Spice Jet they refunded 11, 277 INR. They have totally kept 2878 INR for themselves stating they do not refund conveyance fees and GST.
This is ridiculous. They can deduct processing charge for them as other portal do but looting customer with such a heavy amount is not done.
Need help here.
Kindly give me full refund and close such portals.