Mine having the same problem some time ago. It was charging very slowly and only through USB.
It won't charge on wall or car chargers regardless of cable I used.
If you have similar symptom, try to clean the port

- use needed or pins and pry out the stuff in there (be careful not to damage it)
- use compress air. I used bicycle pump + needle to pump soccer ball and it worked)

If still not OK you probably have a damage port and need to be replace.

Might not be worth it...