Problems with group chat pls help!

[nxraven]

Hello, Im having really weird problems with my group. Im creator and have my store, and group for the store. I have found out that people are keep sending chat advertisements when im not online and in chat history i cant see anyone wrote anything except my notices. It is weird cause i unchecked option for 'Everyone' in the group that they can't join the chat but they still can. Advertising is not allowed in my group and I never noticed this issue before few minutes a go when I have found that out. Please help, and thanks in advance!