Can a business tell someone they will receive a bill credit and then say they are required to fill out a rebate for the credit?

While ordering direct TV, the indicated I would be getting bill credits for the first 12 months. They are now telling me that I did not sign up for the rebates that are these credits. Can they legally state they are providing me a bill credits for 12 months and then later tell me I was required to sign up for a rebate? This seems like an illegal and deceptive business practice.