What should a person do after having caused the spread of a certain song among his acquaintances, regretting it, knowing that he has not repented from listening to songs and still listens to them, and his concern is the ongoing sins?

Singing is of various types, and not all singing is forbidden. If the aforementioned song is of the forbidden type, then the questioner must repent to Allah and cease listening to it, then advise others to repent from it. The questioner's repentance and regret over listening to it are among the strongest reasons for his exhortation against evil to be answered. The questioner's listening to songs does not exempt him from the obligation to enjoin good and forbid evil. A person who commits an evil act is obligated by two things: to repent from it, and to forbid others from it. Neither of these obligations is dropped by the performance of the other. The questioner must repent a sincere repentance from forbidden listening, for persistence in it makes it one of the major sins. If he repents a sincere repentance, he is absolved.