Customer provided image from USPS that they misdelivered. Do I refund customer?

My customer said they didn’t receive their package. The tracking says “delivered inside mail box” but they didn’t receive it. I asked them to make a claim at USPS and a few days later they sent me a image from USPS that had “misdelivered” written across with her name on it. The image looks like my package from a security camera inside on a USPS counter. What is the next step I should take? Is it my responsibility now to refund them?