There was a rattling noise then the freezer started to loose its tempratur?

A rattling sound was heard and when investigated the freezer and fridge had lost their temprature and the food in the freezer defosted. The power freeze was tried but still the freezer did not work. there is a sound that something is working but this is not anywhere as loud as it should be, my first reaction was the thermostat but what would explain the noise?