ANSWER:

No problem in not talking to them. The problem is if you were to see them or meet them and you turn your face as if you had not see them and not give them salam or return their salam. 

QUESTION: Sheikh. i used to have friends before and i left them permanently because they used to hurt me. so now am i sinful to not talking to them from so long ? because i have heard that it is not permissible to a Muslim to stop talking to another Muslim more than three days ?