Sorry to hear you had troubles with yours.
I have 2 and they are charging about 20 hours per day.
With three of us in the house that vape, we go through a lot of batteries.
When both D4s are full I start using the Efest.
My ONLY complaint about the VC4 is it is more difficult to remove the batteries than my other chargers.
Since it doesn't provide a gap at the top of bottom of the battery, you have to use a fingernail to remove it or try to get a grip in the center of the battery.
I just haven't had as much luck.
I can say that when I do use the VC4, I like everything about it except removing the batteries.
Before now I hadn't thought of adding a ribbon for battery removal just like a mod has.
Wow, I may just give that a shot.
The more I think about it, I really like this idea.