Tried both of these.
Finally wrote them a letter reminding them they had to heat the place or else I’d call the city, and the landlord’s response was quote “Why are you doing me like this?”
They evicted one guy who stopped paying his rent until it was fixed.
The other tenants are cold, too, but they’re afraid of eviction and need the place for the location. They also don’t know that they can have reliable heat from the boiler because they’re newer to the place.
So why didn’t the Lux thermostatic switch work? I use them to cycle house fans with the temperature and they work great. Are the heater units 220 volts? You can get 220 volts thermostatic switches as well if you need those.
If you definitely plan to move in the spring, check your local eviction regulations. Possibly you can stop paying the rent now, and it may take months for them to legally evict you.
Another idea is to go to local TV news “action reporter” or whatever is available, and make a big deal about it, have it on the news... ?