Any good quality Micro USB cable will charge the Melomania 1 case effectively.
You will need to ensure this is fully connected by pushing until there is a mechanical click sound and the battery indicator on the front of the case lights up.
There is a cable supplied within the box for this purpose.
To charge the earbuds, simply put them back into the charging case and charging will begin automatically. The earbud status light will pulse white when charging and switch off when they are fully charged.