Depends. Did you have them sent to you or did you pick them up? If the former you can lodge a dispute with eBay or Paypal but if you picked them up, there is no buyer protection and you'll have to work it out with your seller, even though you wouldn't have known they'd leak until after it rained.
Firstly, how do you know they are "leaking". I assume you mean they have water ingress? How did you find this out? Did you fit them to your vehicle? Did you submerse them in them?
