If your charging cable refuses to unlock from your car, here's a simple trick that may help. The locking actuator may just be stuck. In this video I show how to release a stuck actuator.

FYI, on BMW i3 there's a blue release cable located behind the right rear passenger door that's supposed to retract that locking actuator too. But if you can't get to that cable or it breaks or simple doesn't work, try this trick. It's worked for me.
Hope you find this helpful.
The EV Nerd