Of course the seller is going to CLAIM they're sterile. They have to do that to comply with Ebay and Paypal policies.
But they couldn't expect any repeat business if it were really true. In reality, nobody pays $40+ expecting to receive half a dozen sterile hemp seeds.
I say, don't give up until you've tried to germinate ALL of them. You never know.
If none pop, contact the seller and see what he says. You should expect nothing less than another full batch in the mail or a full refund.
If the seller won't send you replacement seeds, leave neutral or negative feedback on Ebay indicating the seeds were all sterile as a warning to any other buyers.
What's the seller going to do. . .respond to your feedback saying that of course they're sterile. . .thereby ensuring that nobody else ever buys seeds from him again? The very fact that you *might* do this is strong incentive for the seller to do the right thing here. In fact, any suggestion that you might bring Ebay/Paypal attention to the seller should induce them to do the right thing.