You can double check the fare class or booking class, but this strongly smells like a mileage broker. It is an invalid ticket because it violates the T&C of the UA FF program that miles cannot be sold and money cannot be paid for FF (award) tickets. You have been warned.

BTW have you checked the record locator yourself directly on the UA website or just on some attachment they people sent you or on their website? Clicking from an email or third party website could send you to a fake PNR created by a sophisticated fraudster.