The $25 mail in rebate is not valid for purchases before July. 27th. Newegg confirmed this in an email reply.
I am not sure what the $25 mail in rebate was back on the 21st but Newegg showed the same $25 mail in rebate along with their $15 instant rebate on the 25th and the 26th. To me and a legal friend their add showing the price including the $25 rebate is false advertising, and they could be liable for the rebate price. At the very least you can cancel the order, and may have to pay return shipping if the product was already received. If it is en route, you should be able to refuse it and call your credit card company to refuse the billing.
Trying to get the rebate or return shipping dollars out of Newegg would probably cost more that there value, if they decline to accept their false advertising. At most they they could get fined or just get a bad mark from the better business bureau. In essence the rebate does state the the dates purchases are valid, and the rebate is available for viewing. The false advertising that they show the rebate in their advertised price before the rebate is valid.