I would try applying a little DeOxit to the shaft of the main switch to see if that helps. If that doesn’t work, then your next best bet is to repair or replace the pedal. Repair seems to be the most economical but not guaranteed as to whether it will fix it or not.
You can try to either replace the main switch yourself or have a repair shop take care of it. The switch part number is in this post: BeatBuddy (BB) Main Switch Broken - #2 by BrennanSingularSound however, the video for disassembling the pedal no longer seems available. I’ve tracked down the new web address for the video of the disassembly and it’s here: Beat Buddy Drum Pedal Disassembly - YouTube
Please let us know what you do to get it fixed.