(I'm from UK)
You contact the seller - and allow them enough time to respond. Not everyone keeps a close eye on their emails: they may just deal with such things at the weekend. If you get no response from the seller, you go through the Ebay complaints procedure.
I suspect that someone who ordered a cake tool is quite annoyed about the belly bars they received.
You don't contact Ebay customer services for issues such as this for goodness sake. How long ago did you message the seller? You have to give them time to respond not everybody sits on their computer all day perhaps they are busy or have family problems? You need to wait 1-2 days after contacting the Seller for a response. Always use the "contact seller" section to resolve issues so the conversation is recorded by ebay, never send a private email.
If you still have no response 2 days after contacting the seller then this is what you need to do. Simply go into your "My Ebay" section & at the end of the line which shows the item that you won/bought there is a down arrow. Click on this arrow & it opens up several options one of which is "Resolve a problem". Click on this & choose "Item not as described" & there is space for you to explain what has happened ie you paid & have received the wrong item & the seller is not replying to your messages.
Ebay then investigate the matter & unless the seller responds & sends you the correct item you should receive a full refund into your Paypal account in due course.
Easy - just open a dispute saying item received was not as described in the listing. Ebay will take it from there.
Ebay should have a customer service number. I'd report them if I were you
