This is disappointing. There must surely be checks and balances in place to weed these kinds of problems out much earlier. Whats important next is to explain how this has happened and what you are doing to remedy it so it doesn't happen in future. If the studio doesn't explain this then its another communication blunder that your just stacking one on top of another. Its not the fact that Iron Banner isn't happening this week that is the real problem. These things will happen during ongoing development. Its the communication of 'why has this happened' and the 'how do we fix it' that are important.