Caveat emptor. Somehow I trusted that, even though the item I purchased at a significant reduction was marked as previously returned and, thus, non-returnable, I would be within reason to expect it to function. Boy, was I wrong.  There were indications that I shouldn't proceed with installation ( shards of plastic, random pieces in the box).
But I was sure that the item must function: why else would it be re-sold by a reputable retailer. My stupidity. There is no way this should have been re-sold. Willing to pay for my own mistake, but will never trust All-Modern again. Hope it's worth the 20 bucks to you all.