these really are terrible machines (I OWN ONE) and found that it has to be on charge for a long time before it will work properly.I've left mine for so long it was completely dead (several times) but after a few attempts at charging it seems ok.
try putting on charge for an hour and turn off unplug leave for a while and repeat a few times.(seems to work for me ) You can only try???
I must say though when working properly they are one hell of a torquee little machine
colin, August 2010