Usergroups error

[School-Help]

I was trying to create a new usergroup so after a certain amount of posts people would be able to access certain areas. After doing so i changed my midn about the whole idea and deleted the usergroup. I then refreshed and nothing changed that user group still appears there. Even now! Also i added a promotion that i want to delete but i cant view it for some reason ? I'm stuck on this because the usergroup i deleted still appears , even when i click on it i get the following message --------->....usergroup id:9 does not exist. Or something similiar.

What has happened? This is important as my whole username system may be comprimised. Is there anyway to restore it to its default just the usergroups?

Thanks in advance