My experience has been that the real good ones ONLY charge me the return shipping, if that. A lot of them have a return label, shipping paid, included in the package so that if I do have to return the product it's free. That said, there are still some who are so short sighted, they don't realize they'll never have a customer again by making you pay for return shipping, restocking, etc.

I think you're probably stuck now that you've already completed the return, but certainly no harm in calling and asking for a supervisor.