Drop Shipping from Syncee

Hi I am trying to add handmade products to my Amazon account, I am using a supplier from the Syncee app so I don’t actually make the products myself, these are genuine authentic items made in the country of origin, Amazon support just keeps sending me help links & they don’t help. Can you actually add items from a drop shipping supplier that makes their own handmade individual items with out bar codes or GTINs to Amazon or am I just wasting my time…. Thanks frustrated !