Hey Ash,
Sorry to hear about this unfortunate predicament! Sounds like there was not good communication from the beginning. How many of your complaints against this tenant are violations of the lease and could be used to lawfully end the lease? I believe that would be the best direction to start looking into. Taking an aggressive stance or implying something bad will happen to them if they don't shape up will only lead to legal trouble. I think there is some great advice in this thread, but as a landlord, you must take the high road in every situation. Be firm in your stance, but do not take matters into your own hands. We have a legal system for that.
Some helpful advice for the future: Before signing a lease with the tenant, I always give them a call a day or so beforehand and go over utilities, pet fees, expectations, contacting pm, and general things on the lease. I find that this helps keep the tenant on the same page. We cannot assume they read the lease, unfortunately.
Good luck!