I had the same issue at first, but that was based solely on the fact that it is unregulated. By using a low resistance cargo (typically around 2.1 for boges) the voltage going through was only 3.7 and the wattage would be around 6. Now that I'm using the kick I'm able to get the carto to perform at about 4 volts (8 watts) which is where it should be for me. The other nice thing, and I'm sure you know this as well, the kick regulates the battery so where before I might have gotten a bunch of good hits at first, as the battery was being used, the output was dropping so I wasn't getting the power I need for the type of vape I wanted.
I hope you get your issue solved my friend, and let me know which cartos you are waiting on as I'm thinking about buying a batch of cartos from a vendor I won't mention here.