Hi. I am sorry that you are having issues with your equipment. It sounds like you are having cartomizer leaking issues. It is most likely that if your charger is OK and the correct one for the batteries that you have, e-liquid is leaking into your battery and causing it to fail. I would respectfully suggest that you may either be drawing too hard on the cartomizer, causing it to draw in too much liquid and leak or not properly priming it, causing it to burn through the filler material (also causes leaks) or running it too hot (too high voltage/power). The easiest way that I know of to prime cartomizers is this:
Drip liquid into the mouth of the cartomizer until the filler material is damp. Try not to let any fluid go down the tube in the middle. I rotate the cartomizer as I do this.
Let it sit until there is no liquid pooled at the top of the cartomizer.
Repeat until a drop of fluid comes out of the hole(s) on the sides of the cartomizer. You shouldn't have any fluid come out of the hole in the bottom of the cartomizer.
Put your cartotank together. Do not overtighten. I would suggest that you use a cartotank fill tool (I like the 'slap yo momma' style, personal preference) and fill the tank. Leave an 1/8 - 1/4 inch airspace at the top of the tank. Overfilling can cause issues.
Let it sit, standing upright, for 5 minutes or so.
Draw like you are drinking through a straw, not too hard. Try not to draw until the battery's cutoff < 6 seconds. Let it sit upright for at least 5 seconds between draws. If you get a burned taste, you are either running it dry or at too high a voltage/power (I use 8 watts with all my devices, works for me).
Hope this helps, there is a learning curve with vaping in general and each device has its' quirks that you need to get use to. Once you get familiar with cartomizers, they are wonderfully reliable (I get 30-50ml before they get tight). Sometimes, you just get a bad cartomizer, but I use Boge XL LRs and it is rare for me to get a bad one. Good luck and have fun!