How can I stop these payments?

Firstly let me state that i am NOt on the birth certificate of my child and for 3 years my ex has used my daughter against me.

It first started when we separated, we did not speak nor did she call me concerninging my daughter, she then once asked for her things and for me o take my daughter for the weekend, i hired a van paid £100 petrol to go from london to birmingham went all the way there to find my daughter not even ready or dressed to come with me she simply told me she is not coming with you i just wanted my stuff, at that point i thought ok that is how she is playing it.

I reluctantly waited and patiently she got back in contact again, begging me to come see her and also for me to support her this year alone i have spend over £2000 on clothes for my daughter and also here n there given her my ex a little bit of change, being the nice guy i am.

All this time i was not aware she had put in a case for the CSA, they did not call or text or email me concerning this, then all of a sudden 2 weeks ago they started taking money from my wages without my knowledge and i realised my ex hadnt spoke to me for about 3 weeks but usually texts n begs me to ring my daughter.

No she said to me when i confronted her about it, and she said i went through the system to get your money you go through the system to see your daughter, now i am at a stage i want to abadon all parental rights and not pay her anything through these scum CSA.

I am not on the birth certificate and no one on earth can force me to have a DNA test what do i do to stop CSA payments please help?