portable charger for sansa clip zip

hallo i have an mobile charger intenso powerbank 2600 mAh http://www.intenso.de/produkte.php?kategorie=32&&produkt=1330688049 but he dont charge my  sansa clip zip player

can I not charge the mp3 player with a mobile battery charger ?

Maybe it’s defective.

Did you charge it before? Did it charge another device, a phone, for example?

I own a similar product and it works great.