Item paid-sent-attempted to be delivered and missing (UK)

[alerr-es]

Hi,

After being paid for an item I was selling, I paid postage through eBay and sent it, Royal Mail 2nd class, small parcel.

The item was attempted to be delivered once, and the buyer finally never received it.

Now eBay is taking my money back to resolve this case. Royal Mail is not answering emails about it, and no idea about where the item is.

It seems that I am completely unprotected with this issue. eBay just protected the buyer, Royal Mail customer service is null, and it's finally me paying somebody else bad practice when it shouldn't. 

Does anybody know how to proceed to with this? Is this just a matter of using a cheap postage service that we are not even heard??

Thanks