How should one deal with a neighbor whose house is used for committing immoral acts, and is silence about that considered a sin?

Efforts must be made to prevent evil and to inform those who can deter the girls causing it, for the Prophet, peace and blessings be upon him, said: "Whoever among you sees an evil, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith." As for dealing with neighbors, the principle is to treat them well, invite them to Allah, and enjoin what is good and forbid what is evil with wisdom. However, if associating with a neighbor harms one's religion or worldly affairs, there is no sin in abandoning them.