Damaged goods

Upon being notified that a parcel has been damaged in transit I requested the parcel to be returned. 3 days later they delivered the damaged parcel to the customer. I have again requested that the parcel be returned, yet they now demand payment before doing anything. I paid for successful delivery, which did not happen, now I have to pay again to get a parcel back that they damaged. Why wait 3 days before informing me of costs, that I do not agree I should pay.