No Way to Charge MP3 player

I sent an e-mail as well from the cokerewards site. I spent 1500 points on the mp3 player. I was able to download some music to it and use it for about 3 hours. I assumed the way to charge it is to plug it into the USB cord on the computer since there were no instructions otherwise and no charger that came with it. That does not work. So after using it 3 hours, it doesn't hold a charge to play any music on it any longer. There should be more instructions on how to do something basic like charge the player. Not happy at all. Very disappointed. I've had such a good experience with cokerewards for the past 2 years until this.