It sounds like the typical downwards spiral of people refusing to listen to what was asked of them, and refusing to engage, and therefore getting judged on that.
As your dd and you have now experienced, you cannot ignore SS or get angry and start throwing around accusations which are understood as excuses and a sign of someone who cannot engage with the system.
The requirements may have felt unnecessary to them, or you, but that's not a reason to ignore them, as you will be assessed as failing them whether you see the reason why or not.
The really sad thing is that it sounds like the wider family carried on the same destructive pattern and did the same, refusing to engage, ignoring the rules set etc, and therefore got the same result.
It is just so sad because it's a familiar pattern that emerges time and again when you hear about SS engagements and the sad ones where the families can't seem to turn it around in time.
And it always sounds confused and fraught with misunderstandings and like the people involved don't 'get' their role in what's happening.
To be brutally frank, there is no other way. Full stop. All the arguing and accusations and conspiracy theories in the world will not help you. In fact they will have the opposite result.
If you are really committed to getting your grand daughter back you need to break this pattern of behaviour. You need legal advice to see if there is anything you can do, or if it's too late. And then you need to follow every single tiny thing you're asked to do whether you agree or not. That's the only way you'll get your gd back, of it's still possible.
I do feel for you, and I wish everyone in this situation the best future possible.