I agree with you kdm. Chanelle has clearly said that nothing happened between them but that is not the same story that Ziggy is telling Liam. Must be pretty embarassing for her!
She said it and later he said it to her- I think she had been told by BB to not discuss the outside world, just to go in there and do the task. If they started up a conversation the chances are she would have to talk about the world outside/how he was doing/what work she had got etc. Maybe she was trying to play it safe so as not to jeopardise his chances in the last few days?