Is it true what an introverted person does, abandoning those who harm him after warning them, and only inquiring about the well-being of those he associated with out of necessity? And if his behavior is not correct, how should he act?

The rulings regarding mixing with people and isolating oneself from them vary according to circumstances. A Muslim must be guided by what serves the Shariah interest. Helping those who seek assistance is good, for a Muslim who helps his brother receives Allah's aid in this world and the Hereafter. Inquiring about people's conditions was part of the Prophet's guidance, peace and blessings be upon him, as long as it did not distract him from more important matters. If you are harmed by someone, work to protect yourself. If what they did is impermissible, then advise them. If someone persists in harming you, you have the right to abandon them if that leads to them ceasing the harm. Abandonment is permissible for someone whose conversation brings about a deficiency in religion or harm to oneself or one's worldly affairs. The greater good must be considered, as sometimes reconciliation is better than abandonment.