If you go to eBay's Resolution Centre and open an Item Not As Described dispute, they will want the seller to send you a Return Shipping Label.
Although this has not been possible unless both parties are in the same country, eBay seems recently to have become aware of it.
Worth a try anyway.
If the seller is in North America, this could work itself out.
The first step is to ask the seller for the return postage (sending the wrong size is his responsibility, after all). If he is recalcitrant, then go to the Dispute.
If you cannot resolve the problem between you or through eBay's Resolution Centre, you can leave appropriate feedback and resell the rods here or on an online local classified website. (With the correct measurements, of course).
And remember , you can catch more flies with honey than with vinegar.
Politely-- Captain Malcolm Reynolds