Is one who avoids a person who has repeatedly wronged him and has not supported him in a crisis, and withholds knowledge from him, rewarded?

It is permissible to shun an offender for three days only, and shunning ceases with a greeting or its reciprocation. However, if associating with the person causes harm to one's religion or worldly life, then it is permissible to shun them for more than three days. Forgiving an offender is a noble trait. As for concealing private news, it is permissible, but concealing obligatory knowledge is not permissible.