I always ask for a photo before deciding what to do, and it doesn't have to be in a "pics or it didn't happen", way. 

A very standard response from me would be to thank them for contacting me about the issue, apologies that there seems to be a quality issue, and then a request for photos of the damage so that I can know what the best resolution to offer will be (I also often need to see the fault or damage to help determine any flaws in the items I sell and/or packaging methods I use, so tend to ask if the packaging was damaged in any way on arrival), and that I will do my best to resolve the issue for them ASAP (solutions offered will vary, depending on the level of damage and whether I can still use the item, and/or how I believe the damage to have occurred. For example, too much damage to make it worth my while to resell or what-have you, refund without return - if they're still fully usable, partial refund or full refund on return).