Delivery issue

[betlocking-sharp_0]

Can anyone advise please - I sold an item and posted with Royal Mail. I sent it signed for and have proof of postage (this was 2 weeks ago) the item still hasn't been delivered and the buyer has requested a refund. (Expected) my concern is the fact my insurance from the Royal Mail doesn't cover the posted cost just the item cost. What do I do? I have proved I have sent the item. I have also proven I've been in contact with the Royal Mail - its literally just one of them unfortunate situations. This has never happened to me before and I sell here and on other apps . 
regards 

[jckl1957]

Unless you have proof of delivery, if the buyer has opened a case through Ebay, you should refund them.

Your claim against Royal Mail will cover the cost of the item (as long as the cover was sufficient - Signed For only covers up to £20 - and the item was one covered by the service you used) and the postage cost you paid.

[john1297576]

Buyer has to open a not  received case and you refund in full.

Using second class post if you claim, RM will only pay out a maximum of £20, it is up to you to use the  correct method of postage, that is signed  for, if over £20.