If you spent on this banner, I'd be sure to get a ticket in. If you haven't spent on it yet, I'd be thinking about doing so before official announcements come out. I'd be surprised if they don't just refund everyone's lapis. False advertising is a hell of a quick path to a dead game.
I'm not sure what else they could do. They could BS their way out of it, call something a typo, etc. Only other legit compensation I could see would be a % reimbursement or giving everyone a Regina for each step they pulled on.