BB are doing everything to save the girl - which is not good in my book.
Charley has a false impression of her own importance (e.g. she believes the public are voting as to whether housemates have upset her or not - e.g. Emily's 'racist' word [evicted], argument with Shabs [evicted], Seany plays pranks on her/pushes in pool [evicted], and now she tells Billi that he is the problem within this house. This is made worse by BB trying to save her at every turn. When she does eventually go, she will be so shocked at her reception...
Billi needs to stay at this point because it should deflate her ego.