Is it bad if Im on NC but my sister talks to my ex because they are friends?

[loverboy1984]

My sister and some of my relatives are friends with my ex. They comment on each others stuff on facebook and text each other. They dont talk about me and I have told them not to. But Im doing NC and want to possibly get her back and I feel like she wont miss me if she still has my family as her friend. Or would she miss me if she sees that my family still likes her and that shes lost me and she may lose them too.