Black magic is very dangerous and is generally used to cast evil spells or to do bad to someone. It is known as Kala Ilm in hindi. Black black or Kala ilm is commonly used by people to do bad to those persons whom they feel jealous from or to take revenge.
A person may get affected by a spirit or ghost problem and be possessed by evil soul. Ladies or girls are often possessed by evil which is sent on them by someone who want to destroy them or take revenge anyway. If this problem does not solve in time, it may kill the possessed person.
Feel free to contact baba ji as following to ask your questions or solve your all problems. He will guide you all.