You could go back to the store where you bought the item and ask them for a replacement. Look very carefully at any embossed wording on the item, or a tag that is fixed to it, and try to find the company that made the item. If you can find an address for the company, send a letter to their customer help office to get the information that you need. If this battery is not removable, then the item will have to be disassembled to replace it. If it is easily removed, take it out and take it to a store that sells batteries to match it with a new one.
