My ex-girlfriend has custody of our daughter and has changed her last name from mine to the same last name as her step-father me or my family have not seen or spoken to her in over 3yrs but my ex still wants child support I feel I need to give my rights up and let my ex and her husband take responsibility for my daughter without them harassing me anymore they both call all the shots anyway does anybody have any advice

Child support is dealt with separate from the shots she is calling.
Why aren't you having visitations or a say in her life?

When the name change took place were you notified ? Did they seek your permission ? Why do you want to give up a child so easily ?

If the step father wants to adopt, yes you can give up your rights and child support will stop. But you have rights to visit, if you will go to court and get them.