Note: Any charger used should be 3A or less current output.
I recommend this LiFePO4 charger (Single battery charger) http://www.batteryspace.com/Smart-Charger-0.7-A-for-3.2V-1-cells-LiFePO4-Battery-Pack-100-240VAC.aspx
If your batteries are allowed to deeply discharge it's possible these charges won't recharge them. This would only happen if the Hiface was left turned on for 24 hours or longer. If this happens contact me & we will get you sorted & working again.
For people outside the US, I have talked batteryspace into using the cheaper US postal service for delivery rather than the ridiculous $70 - $80 Fedex or UPS charge. Here's what they said to me:
Warning: Check the battery charger sticker before use for the first time. One person was sent a battery charger for 2 cells which outputs 7.2V instead of 3.6V. This overheated & killed the batteries causing them to leak into the box. The Hiface stopped working & was returned to me!