So I have a buyer that purchased 2 brand new macbooks from me both have different size hard disks. He purchased 1 at first but change his mind on the size and purchased another one and was going to return first one without opening it but "his son" accidently opened it. He agreed on a partial refund when he returns it but now he opened up a case on both of these macbooks for reason changed mind now both of them are opened. I received the return but I am not able to do a partial refund. How would I proceed, and I highly doubt buyer will close the return. Is my only option to escalate the case?