The truth is, you've been fortunate and haven't had to deal with a difficult tenant until now, so you haven't learned the hard lessons and you failed to prepare for the inevitable nonsense that landlords have to deal with.The law gives you 30 days to deal with the deposit, but you chose to wait and hope the problem would go away.

Your property manager is the only one that will tell you the truth, “No I won’t manage that property” and have to put their money where their month is when it comes to how much money you can collect for rent, clientele, area, etc.This is an ongoing relationship, and a good manager can refer you to other contacts.Ask for referrals.

With that being said I believe there are multiple approaches to a situation like this. 1, being you let them out of there lease with refunded rent from all paid months the tenants have paid. 2, You take the safe and correct approach and get it tested and properly cleaned if needed to continue to be a potential success landlord, not testing or cleaning a meth infused house is very bad for anyone to live in, so you just continuing to rent it out without finding out the truth behind it all, would make me hope you don’t continue in this line of work.

Unfortunately most of the folks on BP don't want to hear the bitter truth.

I have gone through the ProjectRE course and truthfully it was one of the greatest hands on trainings someone wanting to invest in real estate could get.

It’s a lot easier to keep your full-time job as security when first starting out, and for many people it is the only way to begin what they hope is an exciting and successful new career.The truth is that many agents began as part-timers, and some have remained that way for many years.

Quote from @Pouya Banki: You've learned the truth about home warranties.

However I do intend to share the truth.

Truthfully, there are a lot of nuances about getting the refinance that is too long to write about here but take time to learn about it because it is very important.  

This is a simple truth proven time and again throughout all of history.