Seller should pay, or possibly eBay cover it, if those are actual functional parts. Go through the returns procedure within eBay. You'll get a few tick box options for why you are returning it. As long as you tick the right options the you won't pay and it'll give you a postage label to print. They do sound a bit like optional extras to me (although I know little about coffee machines) so it may just be a pitfall of not buying from a shoo

Portafilter and baskets are integral

Item not as described. Have you contacted the seller? I think ebay will expect you to at least give that a try before they'll weigh in but you won't be responsible for return postage if it comes to that.

shows what should be inside the box.

All sorted
Return sorted and label printed
Reordering from John Lewis