How do I respond to a sister who holds a grudge ?

I have a suspicion that there is a lot more to it than just what happened with the phone call. It sounds as if your family has had other problems also. Personally if I had made an effort to make amends and they did not respond I would just figure they were not going to change their minds. Do a little soul searching and see if you can figure out what the real problem is. As for myself I wouldn't want to be with them if I was not sure that they truly wanted me there.