I am prepared for abuse so fire away!!!...
Little back ground... My ds is little over a year & was the surprise but happy event of a casual type fling. (Neighbors & friends 1st turned into a sex thing no talk of long term) anyway the Dad wanted me to terminate & I didn't/couldn't do that so chose to go ahead with pregnancy knowing I was going to be a LP (although secretly hoping he would come round to it)!
He didn't!!! Fast forward a few months.. Ds was 8 months, we had both been ignored by his dad. I had payed for & done it all by myself... Tired, emotionally drained & badgered by friends made a claim for CSA... He only then contacted me to have a go about that, made us going through DNA testing & refused to cooperate with them resulting in it being deducted from his wages!! Last month the 1st payment due but CSA said he hadn't earned enough for a deduction I assumed his boss (his mate too) was doing something dodgy & that annoyed me so I cancelled the claim figuring if he could go to these lengths then I don't want his money!!! 
Anyway payment has gone in my bank today (£200 + & as I've cancelled will be a one off) so do I draw it out & give it back to him??!! My principles is saying do it (although I am by no means well off), ds wasn't planned, I was on contraceptive injection but I chose not to terminate so should he have to pay... I just don't know really, taking his money has never completely sat right!! But obviously he is going to be angry because I should have stuck to that & never made a claim anyway... We are not on good terms that I could explain all that!! I feel like an evil cow!!! I wish he didn't hate me & reject my ds like this!! 