If ex is telling the truth, can she reclaim CSA payments?

I had been paying csa payments for the last three years until recently when my daughter moved out of her mothers to live with her boyfriend and his parents, having before this being living with her grand-parents, since then apparently she has moved back home the child\adult in question has now turned 18 and she has stated that she is now claiming jsa and is not in education, if this is the case and the truth is being told then is it possible for her mother to reclaim any csa payments after the claim has already ceased previously I have had many discussions/arguments with the csa advisors in the past but never get a straight answer about anything I’m guessing that I would not be the only one who experienced this.

Thank you for any help regarding this.