Of course they received the money...it's just an excuse to keep you from the child(ren).
The only exception to CSE NOT forwarding the money is if they (the exs) were receiving "cash" assistance from the State and then the state keeps all but I think $50, since they have in essence prepaid it. And if they were receiving "assistance" when you weren't paying, then your arrearage payment is kept by the state.
and when I asked support enforcement for proof all I got was statements telling me CT recieved money I wanted more proof they told me thats all the proof I needed and was gonna get.
And that's all any NCP gets and all they need to get. But I suppose you could push in the issue in court, but that would require your exs to get on the stand and say that they never received it and they are NOT going to go that and then you will have wasted a lot of money in attorney's fees and court costs.