I agree with what has been written so far and also want to add another technique to your arsenal. Try turning the focus onto them instead of you. Ie. - they are calling completely focused on your behavior and what they can criticize about it. Instead, turn the focus onto them. For example, if your mother says, "you are a weak person and that's why you married your husband," you can respond, "Do you feel that you did a poor job raising me - that you raised me to be a weak person?" When your siblings call and interrogate your children and then call you back and complain, you can respond something like, "Do you feel that it's your responsibility to continue to "raise me"? I wonder why that is. What do you think?" You see the point - get the conversation focused on them and their behavior in hopefully a non-critical way. You don't really want to stoop to their level and get into a criticism war, rather just ask them questions about their own behavior so that they are thinking and talking about that, rather than yours. Awhile of that, and they will be afraid to call you and criticize you, I'm sure. (There really is a "nice" way to do this - you can pick out the "positives" about their questions - ie., they are concerned for you and your children, so you can say something like, "you are always so concerned about me and that's so loving, however, worry and anxiety really aren't good for you. Why do you think that you worry so much? Do you feel fearful a lot of the time?").
This takes some preparation ahead of time. I know I am not really good at "thinking on my feet" when I'm in that situation, so I kind of try to think about it ahead of time and be "armed" with responses like that. In general, just focus on them, and not on the barbs that they send your way. If you get defensive, you're trapped - playing their game, and you'll lose.
The other thing you can try (you can do both of these techniques) is to just tell them non-defensively during the conversation how their comnments make you feel (again it will put the focus on them not you). For example, if your mother says, "you are weak, blah blah blah...," you can say, "I feel attacked when you say that," or "I feel intimidated when you say things like that to me and then I feel afraid to be honest with you." (Don't add anything to that, just be silent and wait for them to respond).
I hope these suggestions will help you change the dynamics of your conversations with them and help you have healthy relationships with them. Blessings to you!