What is the ruling on listening to songs that contain polytheistic phrases? What is the ruling on following someone on social media who displays symbols of disbelievers, or speaking with them via text message where they send some symbols? And what should I do?

It is not permissible to listen to songs that contain forbidden words or polytheism. As for following disbelievers on social media, it is permissible if there is a benefit in it. If the one who displays symbols of disbelief is a Muslim, he should be advised and warned. If he does not respond, he should be shunned and not aided in his action. The same applies to mobile messages containing symbols of disbelief; the sender should be advised, the messages deleted, and not kept, while being careful not to fall into excessive scrupulosity and deeming something a symbol of disbelief when it is not.