Can someone help me figure out this vendor issue?

So I have an online store through SquareSpace. I don’t and never have sold anything through Amazon. Today I received a package addressed correctly to my business and inside were two products that I do sell (again, only on Squarespace site, never on Amazon). With a vendor return slip from Amazon with a “defective“ reason. How could Amazon even ship something back to me that I’ve never sold on there??