I'll start by saying that I'm an internet random and you've only got my word that I am who I say I am, treat it with scepticism and do your own research.
That is shocking behaviour and really concerning to me for 2 main reasons. Firstly they didn't consult you before taking placing your daughter, a minor, in a situation that caused her great distress ie. they didn't follow the law in consulting you and misled you about where she was. Secondly all professionals should act in the best interests of the person in their care and as you describe it they were acting in their own interests ahead of your daughter's, that can be viewed as abuse.
That should have been investigated and if you haven't already I'd strongly encourage you to make a complaint (within 12 months if you need to go to the Ombudsman is straighforward, outside and you'd have to justify why it's timed as it is, easy to do), but it could also be a child protection issue:
https://www.nspcc.org.uk/preventing-abuse/child-protection-system/northern-ireland/
As I said, I'm an internet random but if it hasn't already been I'd really, really want to get that investigated to understand how it could happen and make sure it doesn't happen to anyone else.
That's our experience here as well and it makes me really sad and angry. 'Austerity' has had a huge, but invisible to the masses, impact on health and wellbeing for a lot of people in the UK, people who could once contribute to their community and lead meaningful and productive lives find their support removed because it doesn't fit the financially prudent (ie. cheaper) recovery model. Most of the support is only ever short term and has led to people leaving jobs, having a measurably a poorer quality of life and in some cases much worse.
Also, the decimating of the legal aid system has meant that most can't argue their case even if there are the occasional victories:
http://www.bbc.co.uk/news/uk-42862904
Really sorry to hear that.
Despite what I've said above I still think there are avenues you could follow but local knowledge is also important and I don't have that. For example, in England and Wales the Care Act 2014 places a responsibility on local government to assess and provide support to any individual who presents as having a need (not necessarily tax payer funded) but that doesn't apply in NI and I don't know what the equivalent is.
That's sort of where an advocacy service could come in, and just so you know if you do contact an advocacy service they 'should' be independent of both the NHS and local government, there for you and your daughter, not for them.
Of course