Of course it's easy for me to say, but don't worry about "wasting" money. We can't always know what's useful in therapy except in hindsight. I think a T who is willing to sit with her and accept her in all her defiant silence could be giving her something invaluable. There might be a lot going in her head in those silent hours.

I also agree with the idea of letting her choose a T (or have input into it). Also, do you go to therapy with her at all? It might be helpful to have some sessions together (maybe with a different T though). At very least she'll be hearing how much you care. I read somewhere that parenting is the very definition of playing the long game. The impact of your loving, gentle persistence may not be evident now but that doesn't mean it's wasted.