no name media player won't charge
 

So we got three 16gb touch screen media players from ebay for our kids for christmas. They used up the batteries and now they will not charge. The screen says its connected and the little battery icon in the top right corner shows that its charging but stops after about a minute. They have no name that I can find but ver: 1018_090212_dev_tp_CM_OV_S. All they came with was head phones and a usb cable. I've tried using a phone charger but nothing happens. can anyone help?