My item has been lost by Evri, How do I claim?

Hi, I sent a parcel out to the buyer and I have had confirmation from Evri the package has now been lost. Evri told me as the postage label was purchased through ebay, I am right to claim through ebay and then ebay claim from Evri. I am wondering how I do this as my only option I can see is too refund the buyer?

If you used simple delivery ask buyer to open a not received case then ebay will issue refund and you keep the payment.