I am sorry that your children aren't with you op, but you, like my sister, don't seem to want to accept what is happening.
She too thought that 'giving her dc to her parents' was the best idea (pretty sure you said on another thread that ss didn't remove them, but you willing gave them up after being 'bullied") and said she was also bullied into it.
She told all who would listen that she was the wrong party, and that ss were wrong.
She also said their reasons were stupid & that all that happened was "a few house parties" (the reports their now carer saw say otherwise)
There were a thousand reasons as to why she can't do x,y and z.
She lost permanent residency when she failed to see how her current relationship was also affecting her getting them back.
You said you have a dp who you live with, who is controlling to a degree & you have been with him what, 2yrs? You have to live with him because your finances do not allow you to live alone. Perhaps address that first, op. remove yourself from tricky relationships (he cheated too, didn't he) & bloody well prove SS that you are a decent parent who deserves to have their children back.
If you really did voluntarily give them up, surely it will be easier, to a degree, to get them back. As in, there is no court order that requires them to be away from you?