Sounds like the battery finally died. Those speakers use small batteries and the sound uses almost no power so it lasts a long time. If there is a way to open the plush try to find the box where the speaker is and try to see if there is a battery. Don't rip the plush open and be careful handling the speaker.
I may be dead wrong because I never owned a Kick the Cheat.
thanks man, i replaced the batteries and it works perfectly! I just need to sew it back up and hide the stitching. I have no plan on selling it, but what do you think it's worth in its condition? the tag that came with it is also frayed.