What is the ruling on going to churches to commit acts that harm people, and what is the ruling on seeking help from a sheikh who treats with the Quran to undo magic?

It is not permissible to engage in actions that harm people, as the Prophet (peace be upon him) said: "There should be neither harming nor reciprocating harm," which is an authentic hadith. If the person going (to such a place) will practice magic or have magic practiced on them, the prohibition becomes even more severe, due to the Prophet's (peace be upon him) saying: "Avoid the seven destructive sins: associating partners with Allah, magic..." And his saying: "He is not one of us who practices magic or has magic practiced on him." And whoever comes to a soothsayer or magician and believes him has disbelieved in what was revealed to Muhammad (peace be upon him). Scholars have discussed the disbelief (kufr) of a magician and of one who resorts to magicians. So, whoever believes that a magician knows the unseen, this is major disbelief. As for seeking help from someone who treats with legitimate ruqyah (Islamic incantations), there is no harm in that.