Correcting mistakes in taraweeh Salaah

Q: In taraweeh I am behind the hufaaz. If they make mistakes do I have to correct them immediately or can they repeat it the next day? And if correcting it the next day do they have to read the full ayah or just half of the ayah in which the mistake was made. What's the hukm of reading mistakes from different parts of the Qur'an. Eg, reading a mistake from the 16th para then from 18th para then from 19th altogether?

Black magic

Q: I am suffering from black magic for more than 3 years. Please help me. I want to know I have seen a dream in which I saw ghusul of dead men that I don't know. Please let me know reaging this matter.

Necklace that has a design of a cross

Q: There is a brother who is now reverted toIslam for 5 months. Few years ago when his mother died, he got from his mother a necklace with a Christian cross as heritage. And he promised his mother to that he also will give it away to his children as heritage. Now as he has reverted to Islam, what he has to do with the necklace? Currently he is keeping it in his house in a box. Can he keep this and give it later to his children. The necklace is a heritage piece which is over 200 years in the family.