Did not get my discount - DirecTV DVR

For DirecTV TV services which include DVRs and receivers, Did not get my discount I ordered att/direct last June. I recall giving the agent my cousin's acct number for the refer a friend. Came back from vacation and still no discount. Did not really get any help from att customer service and direct told me to sign up on the website and i did but to no avail it wont let me because I've been a customer for 4months now. DUH! This should have reflected 4months ago! So now what? What can i do to still get this offer?