Three deliveries with defective lamps!

After we were very pleased with our first purchase June 2012, we need to return the current supplies of Amazon (three shipments)! For the deliveries the burn time was just a few seconds or 1-2 hours in some lamps. It was not set here what the lighting time of 10 hours described managed remotely. As already described by other candidates, is set with a white charger. We now hope for an improvement in the fourth delivery, if this is in the same bad condition, we will not start another try!