You're close. They're both pronouns, but different kinds of pronouns. Non lo voglio più = I don't want it anymore, but ne means 'some of it' or 'any of it'. Remember partitives? Those indicated an indefinite quantity and were words you couldn't really translate to English. Vogliamo delle mele = we want some apples, vediamo dei cavalli, we see some horses... ne is kind of like that.