Midnight Velvet Charged twice for return shipping! Prepaid label, then additional shipping! Internet, Wisconsin

I ordered 3 items from Midnight Velvet, totaling $141.31 with shipping and handling.  When the items arrived they were cheaply made and I  didn't like them.  So, I returned them using the pre-printed return label enclosed with my order.  I understood from reading the information enclosed, that I would be charged $7.98 for the return shipping.  I later received an email confirming my return.  I expected to pay the $7.98, no problem.  I received a bill for $28.43!!!  I called and was informed that I was charged for the preprinted shipping label, PLUS shipping charges ($7.98 is just for the label!!!) and then processing charges for the return totaling $28.43!
WHAT A RIPOFF!!!
I tried to negotiate with them since, no where in my paper work (I kept it) did it say anything about the additional shipping and processing charges for returns.  But, they wouldn't even split the difference!
I certainly will not be purchasing from Midnight Velvet ever again!  So many other companies make returns so easy and do not overcharge!!!