@Christy Miller if you can live essentially rent free and move some of your stuff every 3 months, would you do it? I bet dollars to donuts this person is doing it.
Also, a car is both a terrible and great way to judge someone's income and priorities. Most people opt for an unrealistic car and gigantic car payments, and then need to decide between rent and car payment one month because they're terrible with money. Guess who lost this month.
I drive a 09 Honda Accord. It's full of dings, dents, scratches (I live in South Philly, nothing but street parking), missing a hub cap, and its in "crap gold" color. But I can tell you all my bills are paid at the beginning of the month like clockwork. It's all about priorities and again, this tenant knows exactly what she is doing.
You're learning a lesson, albeit the hard way, but learning none the less. Again, treat this scenario with extreme caution. Here are the steps I am taking:
1. Consulting with a landlord/tenant lawyer, bring up everything and also the fact that the heater is acting up again after just being fixed. That's interesting, you either have a negligent contractor or a tenant causing damages.
2. If you trust the person who is taking care of the heater, ask if there are signs of tampering, damage, etc. If it can be proven, most likely the tenant has willfully violated the lease, and you can begin eviction proceedings much faster (hopefully).
3. The lease is your friend; work with your lawyer to determine what offenses have been made and see if there are breaches. You need something to stick.
I don't know what the laws are like but as I said before, be prepared to dig. in. This person is going to be the bane of your existence for the next 60-90 days until they are evicted. Hope and pray the property isn't destroyed.