Is there a mantra which i can chant to protect my self from black magic and my enemies? If there is then what is the procedure i.e. time for chanting, what to eat,where, when, how etc

Swamiji says:
Yes, there is: the nine letter mantra of Chandi, Om Aim Hrim Klim Chamundayai Vicche.
Morning and evening is the time to chant.Eat pure vegetarian meals.Wherever you are in the morning and evening.
When, I already answered. How,with all the devotion of your heart. You have to believe in it sincerely.