It depends on what you're returning. I copied this from the Returns section:
Return Addresses:
Jewelry:
QVC, Inc.
Jewelry Returns
2200 TV Road
Florence, SC 29501
Beauty, Apparel & Accessories (such as shoes and handbags):
QVC, Inc.
Returns Department
1000 Stony Battery Road
Lancaster, PA 17601
Hard Goods (such as home, electronics & kitchen products):
QVC, Inc.
Returns Department
100 QVC Boulevard
Rocky Mount, NC 27815