You don't need to contact eBay for this, as you have 2 choices.
You either open a case for item damaged in transit, and you will be refunded in full. If the seller used Simple Delivery, you will not need to send the item back, eBay refund, and the seller gets to keep the item.
A partial refund for you to keep the item is entirely between you and the seller, this cannot be enforced.
@craig281986-2008