I sent it signed for 2nd class on 9th July but it still hasn't arrived and the tracking just says it's still with them (on Royal Mail website).
Buyer has been pretty understanding but is understandably getting annoyed now. They've asked for a refund but I can't claim from Royal Mail until 15 working days have passed which wouldn't be for another couple of weeks.
What should I do? I've contacted Royal Mail to see if they can give me any more info about the delay, so waiting for a reply.