DHL parcel delivered according to tracking, but not received?

Hello folks,

I ordered something from an online shop. It was shipped via DHL. According to the tracking information, my package was delivered to my mailbox, and only my parents were home at the time. When I got home and opened the mailbox, my package was missing! I then contacted the retailer, who said they had no control over the shipping.

Have you ever had a similar situation? I'm worried my package was stolen, or because the driver was too stupid to leave it somewhere! What a job DHL does…

You can see it in the photo below.

I would be happy if you could help me.