Tree

Please explain to how part of a person's tree,VA well research on ,can disappear. I was gone for awhile . I finally get back in and some, God only knows who, while I was gone remove a total line connected to William the conq. Mind you I got all MYB info from several geneology resource ,well known ones including Plantaqunet Ancestry, magna Carta , and New England Historical Sec reference center. Explain how this happened. Now I have to put it all back in. I would not have found this out except I was trying to chart all my direct lines to him. Curators in charge please contact me.