First of all, DAMN! Second, epoxy is pretty much the same, though I don't trust the over-priced brands with special (occasionally burping) pumps...too many times I've heard such horror stories such as yours. Third, you know, are you sure you didn't have just resin, or maybe mostly resin and a hint of hardener, or maybe not mixed together well? Fourth, I've used really ancient epoxy, meaning over a decade old and it worked just fine, so the age factor isn't as credible as some manufacturers would have one believe Fifth, there's a possiblity that the QA/QC of a batch was bad...? If it helps I'm drinking a beer for you...hope you get the refund...