I cannot locate a manual, but I checked several Bluetooth headsets and 2 hours is common.
If it's taking longer taking that there is a possibility that the cable has been damaged. Any usb cable with the same connectors should be suitable. Try your local electronics shop.
You could put "usb charger" into eBay to see a lot of cheap generic charges, pictures provided. They should be perfectly adequate for testing purposes. Again your local supplier may have better ones but around the same price Jwin will sell you a complete new headset.
Answers & Comments
I cannot locate a manual, but I checked several Bluetooth headsets and 2 hours is common.
If it's taking longer taking that there is a possibility that the cable has been damaged.
Any usb cable with the same connectors should be suitable.
Try your local electronics shop.
You could put "usb charger" into eBay to see a lot of cheap generic charges, pictures provided.
They should be perfectly adequate for testing purposes.
Again your local supplier may have better ones but around the same price Jwin will sell you a complete new headset.
This is always a last resort.
http://www.jwin.com/product_detail.asp?tab=2&idx=2597