They do not disclose the $300 cancellation fee. And they refuse to follow DOT regulations or industry norms of no cancellation fees within 24 hours.
They charged me $300 to cancel a $286 ticket just hours after I made the booking.
They claim they are an agency and not a carrier, so federal law does not apply to them and they can charge whatever fees they want (they charge a lot of other fees that airlines are barred from charging).