From your description, it sounds like the pump either went or it got clogged. This is probably too late for you, but here are my recommendations:
1. If you have not done a full-on cleaning cycle, do that. Replace ALL the water with hydrogen peroxide. Leave the cap off, and set a folded up washcloth or hand towel on top. Make sure it does not drape over and block the vents on the sides. Set the temperature to the highest it will go (I think it goes up to 105º F or so, and then says HI.) Let it run this way for 6 hours. The cloth is there to absorb water that may bubble up during the cleaning. The heat and chemicals should kill most of the growth. If your system is really gunked up, pour it all out and repeat, the more gunk you can pour out the better.
2. I found my pad and cube started getting gunked up with bacterial growth. That could clog the pump eventually if you do not run the cleaning cycle like they recommend. I eventually started just filling my cube with 100% hydrogen peroxide all of the time, even though it will sometimes bubble over. Put it on a cookie sheet if water could damage the floor.
3. If that did not help, make sure that the thermal breaker is reset by pushing a long pencil or something to poke the reset through the hole in the bottom. It took several tries for that to work for me.
If you are handy, you can find a replacement pump on the internet, and replace it yourself. Use the teardown that I wrote above. There may be a comment or reply in one of those two guides which has a pump part number in it, I can't remember.
4. Lastly, call ChiliCube. If it is still under warrantee, they will fix it. If not, I would hope they would fix it for a fee.