I think there may be a way on the usps.com site...to email a return label for them to print out but IDK details
I when face with returns, either expect them to cover the shipping costs.....for situations when it's a preference thing.
OR it's it's a My mess up like it broke on the way there and they want me to fix rather then replace...I PP the funds to them.
Either way I direct them to how to print shipping labels with Paypal, so they get the cheaper rates.