help, buyer says shoes are dirty inside

[GabySolis]

I have 100% feedback, and not encountered this before. I sent a pair of shoes out, described as very good condition.
Buyer has contacted me to say has received the shoes and 'although the shoes are great condition, there was dirt inside the shoe, and would have expected them to be cleaner inside.
I checked the shoes before sending them, even cleaned them so know they're not grubby.
Apparently they were grubby inside?
What do I do now? Don't know what to say to her. Do I offer a refund? She hasn't asked for one, just saying they were a bit grubby and would have expected more.
Help!

they will be just trying it on to get a bit of a refund. Simply reply back saying sorry aboutthat, wasn't aware of the grubbyness. Please return them for a refund. If they return them then simply refund and relist - I doubt they will though

Thanks, I've done as you said and basically said 'I'm sorry to hear you were not happy with the shoes, if you would like a refund on the cost of the shoes please send them back to me and I will refund what you paid for them.'
Now waiting to see what she says next!