This question already has an answer here:
When I change an app's setting to use mobile data (or not), the changes aren't saved when I exit settings. It's infuriating as, for example, I can't use WeChat at all unless I'm on wifi.
Elsewhere on this forum it's suggested that the only way to rectify this is to restore not from backup. Is there really no other way? And if I do need to restore not from backup, how do I do it? And what will the consequences be - e.g. lost contacts, etc?
Many thanks for any help.