Not really sure if this is ok or not

Is it wrong?

My child’s sperm donor(biological father) is constantly, rudely(name calling, threatening etc.)asking me to drop child support. Says if I drop child support he will sign his rights away. He is behind multiple thousands, and has really never had anything to do with our child, doesn’t ask about them, doesn’t see them, has stated multiple times he wants nothing to do with them, and pretty much acts like they don’t exist. Tells me regularly that I need to drop child support and if I don’t he just won’t pay it, he won’t work, etc just to try to avoid paying child support. All that being said would it be wrong to ask for a lump sum payment from him and if he agrees once the lump sum is received I would drop child support and let him sign his rights away? Or should I just let it all go and drop child support? Or should I just keep him on child support?

I honestly don’t know which to do, part of me wants to let it go, but I also don’t feel like I should be the only one footing the expenses of raising a child. I mean I have been the only one supporting them because he only pays part of what he is ordered to pay in month and he only does that every 4-5 months to avoid his license from being suspended. But I don’t feel like he should be able to just walk away from the responsibility without some type of consequences. Am I wrong and petty? Or no?