When you cancel a Jet.com order in ShipStation, the order will cancel on Jet.com, and the buyer will be refunded. This is the only marketplace integration in ShipStation that will transmit a canceled status back to the selling channel to update the status to Cancelled within Jet.com.
HOWEVER! You cannot restore a Jet.com order from the Cancelled status to the Awaiting Shipment status.
NOTE: Once an order has been updated to the Shipped status on Jet.com, ShipStation will not be able to cancel the order.