Dial damage on a watch?  My first thought was aren't the dials under a glass or quartz cover? Assuming it was sent in a box with some bubblewrap it's hard to imagine how dial damage could occur during transit.

 I agree with asking for a photo of the face of the damaged watch. It may be helpful in that you recognize the watch as the one you sent.

Also be aware, unless the buyer's claim of damage is true, what you receive back is unlikey to be what you sent.