Open a return case, just as you normally would.
Choose the reason 'damaged in transit'.
This will not cause any trouble for the seller. Ebay may ask you for photos of the packaging and the damaged item.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)