They said they will announce a replacement shortly. That is a confident statement. I have no doubts a new act will appear, I just think it will be so poor that leaving it as "TBC" on their poster has a better chance of selling the final tickets than the act itself. Could just be someone doing a DJ set which might be some people's cup of tea but not mine.
The more time goes on the less faith I have it will be anyone decent. If they had a real trump card in reserve then why were they not on the initial lineup and what is taking so long