I don't know what PIU is. An online shop? As I live in France, I ordered it from Ebay.com and they told me to contact the company...which didn't answer.I've had mine for quite a few months and it only once refused to charge, I contacted Randy (as I bought it from PIU) and he said to try charging it again all night, if it does not charge sent it back immediately for a free (brand new) replacement.
I charged it the whole night, it worked the next day.
Sounds like you got a dud but if you bought it from PIU don't sweat it, just contact them and they will work it out with you!
I tried to charge it all night, just as you did. Maybe I'm unlucky : ) that's no big deal.