You need to replace your connector. Go to your local bike shop or if you have the skills, try to do it your self. The pin is called RCA.
To remove the remains of the metal cover from where it remained:
- Unplug the charger from the outlet (and keep it that way)
- Apply some super glue on the orange plastic pin
- Plug the pin back into the battery and leave it for some time so the glue will drive
- You should be able to pull the metal part out from the battery
If you need a new charger, check out these ones: