1. Contact and speech with people should be for the Pleasure of Allah only. For instance, if somebody is a heretic in religion, or commits sins openly, and in spite of the advice given to him, he does not mend his way, a Muslim can renounce contact with him for the sake of Allah. Such renunciation is permissible. In fact, it is desirable so that he may learn a lesson from it and may change himself. But severing contacts merely for worldly grievances is not permissible.
2. After three days, one who should take the initiative in giving Salam is more superior than the other. If the second party does not respond and perpetuates malice and enmity, he will be sinful and the former will be absolved of the sin of rupturing contact.