Do 2 rakat nafal salah. Then read complete Hiz bul behir 7 times. Do this for only 7 days. You can find it in good Islamic book shops. You will win the case for sure.
This is a very Jalali wazifa. Dua Hiz bul Behir was given to Sayyedina Sheikh Abul Hasan Shazli (Rehmatullah alah) by the Prophet (Sallal laho alihey wa aalehi wasallam).
Warning: Under no circumstances do it for more than 7 days or for the wrong reasons. Your life will surely be destroyed. There is no one who will be able to help you.