Help with horrible tenants

[Luis Prieto]

Hi guys, I'm reaching out for help or advice on how to deal with a tenant that I have been having problems with. Short story is that this tenant lost her job last year. We felt bad (horrible mistake) for their misfortune and accepted half rent for some months. They are $2,200 behind, and keep making BS excuses. Anyway, besides being behind in rent, there seems to be a lot of drama between the couple, and it has got us a bit annoyed. Everytime the guy leaves, the women inquires about changing the locks. We asked for a restraining order, and the guy always goes back. What's most frustrating is that they have bought a new gazebo, a new large pool, outdoor furniture and other luxuries while they owe us money. My question is, is there a formal notice or letter that I can use where I demand the outstanding balance within a specific date, and what are my rights. I have looked online for resources, but feel that I can use more clarity, and I trust the opinions of the biggerpickets community much more.