Mine was months out of warranty and exhibited the same behavior; would not charge. Contacted DJI online, sent it back to them, they fixed/replaced it and sent it back to me. Works great. Very good service.
I had the same issue; tried a lot talked to DJI online and they said send it in even though it's out of warranty and my insurance was expired. I did and they replaced it and sent one back to me. Grreat service!