Hi Cielpur.

I would certainly have a word in your sisters ear for a start, as you may just be making assumptions at this point. If she indeed passed on personal details without your permission, then politely ask her to not do this again without ok'ing it through you. As for the other 2...I wouldn't worry or fret about it too much. Them sending you a Xmas card means that they were thinking about you, even if it was a direct attempt to upset you it reveals that they are unhappy in their lives....Otherwise they wouldn't have even bothered.

Please don't take their childish spiteful actions to heart...start the New Year in the knowledge that you are the bigger persons by flipping off their bad form.