How to separate the USB-C cord from a WD15?

Hello,

Some time ago I bought a WD15. It's not working as it should and I'll get another dock. I spoke to the DELL support and they said, that I don't need to send the broken dock back. The only thing DELL want to get back is the cable, that connects the dock with the laptop. I cannot just pull it from the dock, it's stuck there. How to separate it from the docking station? Is it possible to open the dock? I don't see any screws...

Thanks & regards