what u need is a feeling of security and help. There is no black magic that cannot b overcome. Goddess kaali mantra can help u. Find a guru and from him, u can have a mantra. If u think that you cannot find guru, a simple mantra is as follows.
BAAL KAALI MANTRA:
DHYAN: " RAKTAANGEEM RAKTAVASTRAAM KARIVARAVILASATH
KUNDALAAM CHANDA DANSHTRAAM KANTHODYAN MUNDA MAALAAM PARISARAVILASATH
BHOOTA PISACHA VRUNDAAM GHORAAM GHORATTAHASAAM
KARAKALITHA KAPAALAASI RAUDRAAM TRINETHRAM
SATROONAAM PRANA HANDREEM SISUSASI MAKUTAAM BHAAVAYED BHADRAKAALEEM" (KALI MA HOLDING SKULL AND SWORD IN HANDS ALONG WITH BHOOTHGAN, WITH HER BODY SOCKED IN BLOOD WEARING RED CLOTHES AND LAUGHING LOUD)
Think like this and chant the following mantra 27 times in the evening everyday.
MANTRA: "om aem kleem ssau kaalike kaalike devi sarvakaanthipradayini, papasaanthim dukhasaanthim sarvasaanthim dataatu me. hoom fatt kaaleee satrudoshaprasamani nityam nityam namo namah." u should find aguru to know the way of chanting. or jus search mavinmanoharan in face book. JAI KAALI MAA
