The problem I see is you were not firm in following through on setting the rules down.
You could issue a notice violation if they are doing something outside what is allowed on the lease. They will then have several days to remedy the issue. But I would suggest you forget about that and just end the lease when it comes up. If you are month to month you could give them a 30 day notice to be out on May 1st. Then start with a new T with better set rules.