refunding "changed my mind" return , can I withold the Special delivery charge ?

[softwaredivision]

Customer used "special delivery option " instead of our standard free 1st class postage ,,, Can I deduct the Special Delivery cost charged when making a refund for the "changed my mind" return? 

[tobiasd4]

If buyer opened change of mind return, they pay return postage.

On receipt of item, you refund sold price & outgoing postage.

Ebay won't make you refund return postage, up to you if you do..