CSA still harassing despite child living with me

My daughter now lives with me due to her strained relationship with her mother and the csa and child benefit are believing all her lies as I have no parental responsibility at all , although I have paid huge CSA payments for 5 years for one child .

She moved in with me full time in July this year and the Csa are still constantly harassing my payments believing all the lies she is being told by my daughters mum …

How can be expected to look after my daughter full time and and make unessacery payments to the CSA . I AM AT MY WITS END WITH CONSTANT HARRASSMENT FROM THE csa …can anybody help me?