Legal Question in Landlord & Tenant Law in Missouri

Sadly, you may have to formally evict them through the Court. The name of the pleading is "unlawful detainer" and you may be able to find a form pleading somewhere. It would be better to have an attorney draft a custom one and explain the process to you. The little it Woolf cost to have this done, will likely outweigh the cost of failing to get the Order of eviction, and monetary damages. Perhaps even a letter from that attorney would prompt them to move out.

Good luck