Seriously? I was with ATT for two years and I can attest that the ATT forums are chock full of complaints about unfulfilled CSR promises, denied rebates & rewards, lost trade in devices, etc.
Here's just the latest one today:
I'm sorry you're not seeing the 20% discount yet. It should have already been applied. The discount should begin on your first bill after activation unless the billing cycle closes before the discount can be added. In that case, you will receive two credits on your second bill. Has your second bill posted online yet? If so, are you seeing the discount?