Hello and good day. I am sorry to know what happened to your previous flight with your DJI Phantom 4. We highly recommend syncing your flight records using the DJI GO 4 app and contact our support for our team to provide an appropriate solution and initiate the investigation. The repair fee would depend on the warranty of the product and the outcome of the investigation. Just a reminder that if the warranty of the said drone has already expired then DJI will not be able to perform a data analysis for the said drone. You may refer to the link below to contact our DJI Support Team. Thank you.
lvl.1
DJI team