Any Qi charger should work, but you have to make sure the charging coil on the charger is lined up with the charging coil on the phone. Did you already try moving the phone around to locate where the sweet spot on the charger is?
Also, you said that you put the phone on the charger, turned Off but the next morning it is On. Do you mean that you powered the phone down, but found that the next morning, the phone had powered on by itself?