I'm also one of those waiting in the Verizon camp, though I bought my device from the Microsoft Store. I got the email with the $20 code but nothing since then. I have replied to the email but got no information. The keyboard hotline always seems to be busy and I have left them a few messages with no response.
This has been very shoddily handled and I'm fairly displeased. The main reason I convinced myself to buy this was because the keyboard was free. Now, 3 months later, the keyboard is still a mystery.