I don't know what dealer you purchased it from, and actually how long you have owned it. Most dealers (not all) will take back units that fail in the first few days of ownership. After a week or two, your only recourse is to send it back for repair.
The OEM battery is 1,100 mAH, and the upgrade is 1,800 mAH. There is also a rapid charger available. The unfortunate part is, you can't exchange or upgrade them at time of purchase!
These facts are why I ask a LOT of questions, up front, when I buy amateur gear. You can not assume anything. It is also why I don't buy from small dealers whose sales methodology is lowballing.