Or just back to the retailer and tell them why you're returning it. If they put up an argument (which they likely won't), then at least in the US, I think you could sue to be compensated.
If you didn't see and agree to the TOS prior to purchase, and you find the TOS you discover later to be unacceptable, then I'm confident that you'd win in court.
If you didn't see and agree to the TOS prior to purchase, and you find the TOS you discover later to be unacceptable, then I'm confident that you'd win in court.