First, I'm REALLY glad that you weren't hurt! These batteries pack a helluva lot more energy than your run of the mill Duracell.
Secondly, I'm going to chime in with the rest of the people here and strongly suggest that you stay away from ALL rewrapped/relabeled batteries like EFest, Imren, Basen, TrustFire, UltraFire..The way it was explained to me once was this:
If they don't make a TV, don't use their batteries for vaping.
Authentic cells from Samsung, Sony, LG or Panasonic are the ones to go for. You do need to be a little more diligent in ensuring the cells you purchase have the correct amperage rating when buying cells from the Big Four. For example: Go to a trusted vendor like www.imrbatteries.com or www.illumn.com and look at the Samsung 30Q. Then compare the picture of the 30Q with a picture of a Samsung 26F. Both are wildly different batteries-different amp ratings and chemistry, yet both batteries have the same Pepto-Bismol pink wrapper.
Finally, use a trusted vendor to obtain your batteries(Provided you have access to them and are not constrained by your location) The two I listed above are both on Mooch's List of preferred providers of genuine cells. Ebay and even Amazon have been known to be targets for counterfeit batteries, and they're usually more expensive than the suppliers I've listed.
Again-I'm really glad that you weren't hurt! Stay safe and happy vaping. Cheers!