and you are sure the final price is lower than what you booked?
I repriced my cruise a couple of weeks ago and saved $400 off of the original price (no OBC, though). A week later this "great sale" with OBC started, but, alas, the base price increased, so even with OBC the overall price is higher than what I repriced it to.
take screenshots for your CVP. It took mine a couple of days to get to it because she was in all day training.