Hello and good day Sailor15. I am sorry for the inconvenience. Have you tried to check if there's physical damage to the Remote Controller? Have you tried to use a different cable to charge the Remote Controller? Please try to charge the said Remote Controller for a longer time to see if it will accept any charge. If the said remote controller will still not accept any charge I would recommend to contact our DJI support team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. Thank you.
How old is your Mavic Pro controller? It may be that the battery may need to be permanently replaced or it could be the Micro USB input that has become damaged and needs to be repaired???