Family Dollar complaint: Charged for merchandise I did not purchase.

I shopped at Family Dollar, Store 02478, in
Newport, Kentucky today. For reference, my purchase consisted of approximately two dozen items, totaling $130.40 plus tax.
The item in question, was an Accent Rug,
5 X 6 feet, with a price of $20.00; as the young female cashier was ringing up my purchase, she insisted that the package containing the rug, actually had not one, but two rugs in it, so she informed me, that she’d be charging me for two rugs. When I questioned her, she said in a very rude, and matter-of-fact manner, I know for a fact, that there are two rugs, in the package!
I took her word for it, and continued with the checkout process. When I had brought the purchases out to my truck, and showed my husband, we both opened the package, and discovered that there was indeed only one rug, and NOT two. Additionally, the package that the rug was in, is labeled: 5 Ft X 6 Ft
Room Size Rug. (NOT rugs) I immediately brought the rug back into this Family Dollar store, and after confronting the clerk, she adamantly defended, that I had removed the second rug from the packaging, and when I return BOTH of them, then she would issue me the refund. I had asked her for the store manager’s name, and she denied knowing their name. She added, that if I desired a refund, I would need to give her my phone number, which I did. I left this Family Dollar store, as an UNsatisfied customer.