Aha - I see
Sorry for the misunderstanding about using other cables 
Ok - so the two “outer pins” are the power pins usually.
The ones next to each magnet.
I do not think you have a bad cable though.
Normally I would suggest carefully removing the rear cover and checking connections and also checking that the USB cable pogo pins are still “spring loaded”
But as this thing is so difficult to dismantle - I suggest you just return it.
They will be ok about it - email them kospetsmartwatch@gmail.com and explain that Pablo11 from the fullandroidwatch forum has advised you to contact them and arrange a return.
Let me now what they say please.
Cheers