Hello: Do you or a friend of yours have a meter to check voltage and ohms? If so, you can check first that you really are getting 240 volts, not just 120, to the heater (measure above AND below the red reset button). If you have power, check the upper element. You should measure 240 volts across the two screws. Now, with power off and one wire unhooked from the element, measure in the one ohm scale. The needle should move most of the way across the scale. If it moves none or only a little, the element is bad. The thermostat may be bad too, but not if you found 240 volt power at the element. Let us know.
ps. If you’re not experienced with power, don’t mess with it… watch someone else!