Answer to "My handset battery isn't charging. Where do I buy new batteries?"Here is a link to a site where you can purchase a replacement battery. http://www.101phones.com/details/933/son...
Answer to "Where do I find the serial number?"On the bottom side of the telephone base there will be a small outlined area with the device information. The model number is on the top line preceded by "MODEL NO." and then XXX-XXXX.