Candle wax is a typical problem that can be easily solved in a simple way. Scrubbing, washing or scratching will not fix the problem. You just need an iron and paper towels to clean it up!
Place a few pieces of paper towel on the wax candle stain, and start ironing the paper towel as if you were ironing a garment. The candle wax will start getting warm and will stick on the paper towels, removing the wax off the carpet.