Is it only on 240v that she doesn't get hot water? If that is the case, tell her to use gas as a temporary measure.
Sometimes when setting up you may inadvertently switch the water heater on when it isn't full. This causes a protection switch to flip over and cut off the power. It should reset itself after everything cools down, but doesn't always. Use the gas for a day or two and then try on electric again.
Hope this helps, but without further info it is difficult to advise.