If you think you have black magic and you have all indications that it is black magic. Do the following and it will go away within 7 days. Guaranteed by the biggest Wali Allah in sub continent. Sayyedina Sheikh Ali Hajveri (Rehmatullah alaih), who is buried in Lahore in Pakistan. He came from Iraq 1000 years ago and brought Islam to the sub continent. 

Darood/Salavat 11 times

Read “Ya Mumeet-o” (Allahs name) 7000 times every day

It takes an hour to read it 7000 times.

Do a dam (blow) on a glass of water and the person who has black magic on him should drink it. If the magic is on yourself, you drink the water. If it is whole family please make everyone drink this water. Please mix the water with normal water and drink it whole day also. But first everyone should take a sip from the new water every day. Then you can mix the left over water with normal water. Do this every day for 7 days. 

Not only the black magic will disappear but it go back and attack the person who did it to you.