I've been a Vapor4Lifeife customer for a little over a year now. I've had a few bad carts, but not excessive. I bought two boxes last time. I've opened one of the boxes and four of the five are bad. At least I think they are. I filled them and then when I hit the button on my manual battery, it releases vapor from the top of the cart and it smells horrible. (a burning smell) Is it something I'm doing wrong or are the carts just defective?