I just canceled one fly reservation with this company within 24 hrs of booking.
They charged a service fee of $75 for cancellation. I argued with them that by regulation I should not pay any penalty. They said this is service fee not penalty. I will get full refund from the ticket price that I paid. But this is their service fee. I will never use this on line flight booking in the future. Even though their price is always a few dollars lower than other company. But their service cost you more.