Dear Questioner from North Carolina:
The first caveat I have for you is that I am not licensed in your state. I can only give general legal advice from your broad question. I take it DSS is the Dept. of Social Services. Here in Ohio we have Family and Childrens's Services and the like.
If DSS already investigated the false allegation, why are they trying to follow up? What duty do you have to be hailed into someone's office with no legal process being served upon you? I do not think you have a duty to do anything at this point. You may want to hire or get advice from an experienced family law attorney in your local area. Best referral is word of mouth from someone who used this lawyer. Perhaps this lawyer can put pressure on DSS to cease and desist unless and until they have something more than false allegations. It is a crime to make false allegations to authorities.
Perhaps your family member slinging the false allegations needs to be investigated. In Ohio a person who makes false reports can be charged and convicted of falsification, obstruction of official business and the like. My bottom line advice in this one is do not make another move without the advice of a good attorney in your local area and State. Thank you, Nicholas J. Scheps, Esq. Ohio