I have never had any problems with the Q continuing to charge my account for Easy Pays after returning an item; in fact, I almost always see the future scheduled charges disappear from my account on the same day the return is processed.
Just in case anyone doesn't already know this, you can check your current and upcoming Easy Pays at any time by going into the "Order Status" area of your account here at qvc.com and then clicking the pink "Easy Pay" link near the top of the page.