Got the charges removed, but had to tell them to ship me a return kit. They said I "have to use the separate kit" and "cannot use anything that it sent with the new phone to return my old device". I argued this point, and it is probably wrong, but just a heads up to everyone - you may need to request a return kit if they didn't send you one.
I think you also have the option of just taking it to a Corp store to return. That way you get a receipt and know they have it.