Item stuck in the Royal Mail system

[guccishell]

I recently sold an item which I posted the morning after payment was received. This was with Royal Mail using their signed for service. I had advertised I would send 2nd class, but I sent recorded to make sure it arrived securely. The buyer contacted me as she'd not received the item, so I checked the status on the Royal Mail website with the tracking number and it says it's on its way. I also sent a picture of the page including the tracking number to the buyer so she could see that it had been sent as promised. She has just contacted me again to say it's taking too long, she can't wait any longer and wants a refund. I have checked the status again with Royal Mail and it's still the same. I have contacted the buyer to apologise again and advised I will contact Royal Mail by phone in the morning, but I won't be refunding any money unless the bag is returned by her or Royal Mail, as this is not my fault. If the item is delivered, my listing does state returns not accepted.