Your landlord is obliged to keep your space “habitable,” which, among other things, means your primary living spaces need to be heated to 68F if it’s 10F or more outside, or 61F if it’s below 10F out. If they fail to do that, they can be reported to the health department for failing to provide a habitable unit.

I say this not because you should immediately jump to calling ACHD, but so you know what the backup plan is if your landlord doesn’t fix the issue. If your landlord knows you’ll be without heat for a bit (and if they haven’t scheduled a service appointment yet, they know), they should be providing you an alternate means of heating. Usually that’s going to be bringing over some space heaters, but it could also be something like putting you up in another property or a hotel or something if space heaters aren’t an option for some reason.

Call your landlord and ask for space heaters or some other solution. If you run into resistance, let them know the law says they have to. It’s entirely possible your landlord may not know the law. If they do know the law but are trying to skate it, now they know that you know your rights. Don’t be threatening or shitty about it until you absolutely have to.