Can't get an SDS for discontinued product


I have an item under Hazmat review due to children’s markers for 6 months now. They are charging me storage fees for the item I have requested to be returned or destroyed. They insist on an SDS but the item is a Dollar Tree product and is no longer carried and they do not have SDS’s on their products. How should I go about getting this item removed from hazmat or returned to me? Any help is appreciated.