Tenant signed a new lease somewhere else before end of lease

[Joshua Tavares]

Hello,

I am looking for some advice and/or any experience with situations like this:

One of our tenants signed a lease effective 3/1/2021 through 3/31/2022 we pay heat and hot water and the tenant pays electric. When they moved in we went through the lease together in detail before they signed. Fastforward a year we have had 0 problems with this tenant. He notified me last month that he was planning to move into a larger unit in another building. A few weeks ago he then confirmed that he was moving and signed a new lease for his new apartment for 3/1 and was moving 3/1. I reminded him then that his lease was through 3/31/2022. I assumed during this communication that he signed with the new place early as it is not far from our home and wanted time to slowly move his things out (our last tenant did that but of course that's on me for assuming).

A few days ago, he sent us a very passive aggressive message to summarize it said: "since you so kindly reminded me that I will have to pay rent for a month I wont be living here, the heat hasn't worked in 3 months and I deserve to have some heat in here" Mind you, this is an owner occupied multi family so we see this tenant at least once a week and have had several conversations about the unit and how he said everything was going well there. He not once mentioned that it was cold in there or that the temperature wasn't increasing as it got colder (we live in New England). That same day we had our HVAC guy over there to replace the compressor and it seemed to be warming up in the unit. I checked in with him for the few days after that and he said it was warming up and everything was good. 

Today he sends us a message saying its back to 50 in the unit and it's not warming up. He then proceeds to say that he wants his lease to end at the end of this month and that he doesn't want to have to pay for the last month because the house is "uninhabitable" . Obviously we take providing heat in this climate very seriously but not much can be done over night when you wait 3 months to tell us there is a problem. (we have our HVAC guy coming back tomorrow to take another look)

What direction do we take this? We are legally required to provide heat at 65 degrees but didn't find out about the lack of heat until 3 days ago and we took immediate action. I also don't know what possessed him to sign a new lease before his current was up, but it seems like he just wasn't paying attention. 

If we hold firm to the terms of the lease and/or keep his security deposit if he doesn't pay, how could we lose in this situation?