More Troubles

This time it's not the water chemistry; it's the water temp. I bought a brand spanking new "Top Fin" 300 watt heater about three months ago. It's broken....it will not turn off, and so, my water temp started climing. The good news is that I noticed this in time so that no harm came to my fish. Now, I will have to buy a new heater. Anyone have any heater recommendations? I think I was to try something other than the brand I had.