Ebay purchase arrived damaged. Seller told me to contact eBay for refund as it used simple delivery - confused

I bought an item that arrived damaged. I want to keep it and replace the broken part (a watch strap) but the seller tells me as it was intact when he sent it (packed in a too small box) I should claim for damage via eBay as it used simple delivery.

However the only way to do this I can see is to open a return request with the reason "item arrived damaged" - which then says the seller can offer a partial refund, not eBay.

Am I just being fobbed off, and shall I just swallow the issues and replace the strap. It would be nice to get a refund but it feels like a lot of hassle.