Light two black candles and chant:
In the name of the Gods and all ye Spirits
In the name of Kernunnos and the light and the dark
And the Gods of the Netherworld
And whosoever shall be casting a curse against me
Let them suffer their own curse
Let these candles be their candles
This burning be their burning
This curse be their curse
Let the pain they have caused me and mine
Fall upon themselves
Do this spell for five consecutive nights (as close to midnight as possible) and each night.
Chant the spell until the candles are spent.