I want DNA proof before I pay CSA

I met a woman in 1999, she had a child on 13/02/2000. she told me the child was mine, which I accepted. A few month down the line, she told me that the day we first slept together, she slept with someone else the day before, and the child in question my not be mine. We seperated a few months later, she contacted the CSA, and the CSA contacted me, and said I have to pay the childs mother £5 per week, I told this to the csa that befor I pay the £5 per week, I want a DNA test, to prove the child is mine.

I got a call from the CSA, saying that my name is on the birth certificate, and I have written letters to the mother, asking how the our daughter is do. I told the CSA, that at the time of writing that letters, I thought the child was mine. The CSA is still taking money off me, even though I have told the I want a DNA test, and I don’t want them taking money from me, until I have proof that the child is mine!