I have located a Web site that sells some parts for Universal Remotes, including replacement charging base and replacement battery for the MX-3000. Here is the contact info:

AMERISPONSE
Home Page URL: http://www.amerisponse.com/
Phone (Sales): 1 (888) 349-5065
Email (Sales): [email protected]

The easiest way to find listings is to select the manufacturer or search for the model number (MX-3000) at the opening home page. Below are samples for MX-3000 parts:

76901 Universal Remote CHGBMX3000 CHGB-MX-3000 - CHARGE BASE FOR MX3000 REMOTE $120.39
76899 Universal Remote BATTMX3000 BATT-MX-3000 - REPLACEMENT BATTERY FOR MX3000 $99.39