Oh, come off it. They're not trying to help. They're the ones who are sniping, demanding information they have no need for and then when it's not forthcoming, hurling pleasantries at the OP such as it's all her fault and she'll probably end up a lonely old woman in a nursing home.
Nice. Real nice.
OP - you're right to hold your boundaries, no one needs to know your personal circumstances and judging by the tone of some responses here you're right not to justify them here. It's drama voyeurism, and some of these PPs are probably only looking for a stick to beat you with, anyway.
My take on this is that hope is often touted as a positive thing, whereas in some instances there are few forces - even hate - that are more destructive. If you hold onto hope in some situations, you end up living your life in a painful, non-ending purgatory.
The most painful step you have to face is letting go of that hope. If things have reached the nuclear option of NC then there's a strong possibility that this is not salvageable. If the relatives who have estranged themselves for their own self-preservation they are doing what they believe is in their best interests and probably at some cost to them. If they're doing it to punish you, they're likely to be punishing themselves also. This is a very unhealthy dynamic, and one best left to run its course, whether or not that situation ends up permanent.
I've heard it said that estrangement is cruel and in itself a form of abuse. That depends. In circumstances of self-preservation and protection, this isn't so, and claiming that it is might amount to a form of DARVO, a known tactic of abuse. In the case of punishment, it's quite likely to be.
You can do nothing. Don't pursue it: they will double down and it will push them further away. Respect their wish. Let them know your door is open. Then, painful though it is, you have to try to rebuild your life without them. Don't let bitterness take hold. Try to focus on things and people you love: hobbies, the outdoors, anything calming and healing.
I don't know what relation to you these people are, but Susan Forward's books Toxic In-Laws and Toxic Parents are a valuable read, whatever side of the relationship you happen to be on. Don't let the titles mislead you. The books don't deal with incendiary tactics, but offer calmer, peaceful solutions and an increased understanding.
There may be blame on both sides. There may be a primary aggressor or victim. But in some cases, certain personalities might have nothing wrong with them per se, but in some combinations can become toxic to each other. There's a never-the-twain-shall-meet situation between me and some extended sections of the family - I'm not a bad person and neither are they - we just simply don't understand one another and to an extent that's probably insurmountable. That, sadly, is life.
for you.