what is the best way to manage and troubleshoot a shared internet connection across multiple tenants?

Your managers will likely be caught up in doing some digital trouble shooting "it's the App" "No it's the lock".Also if you're looking for some sort of Bluetooth or NFC solution (no wifi), then how do you manage deleting access from the person's phone?

Most likely there was at least two if not more hours of labor involved in trouble shooting and also replacing.

I usually trouble shoot pretty good over the phone or text, so I can work through those issues in a few minutes.

Sure no heating or no cooling could be a much bigger issue, but if we're requiring and reminding tenants to be changing filters quarterly the chances of the heating issue being a quick reset on the motherboard or troubleshooting on the thermostat are high. 

Does anyone have a recommended technician or company that can help troubleshoot / repair a intercom buzzer system for my small multifamily property in Chicago?   

Once out of warranty I’ll troubleshoot but opt for new except for special cases.

Whether or not that's because its going bad or something else is going to be up to troubleshooting.

Surely a tenant would just do it.The ideal situation you described is how it should work-quick troubleshooting with the tenant over the phone for something that could be as simple as changing a battery. 

It also means I spend A LOT of time researching, troubleshooting, and putting in way more time than needed to get an answer...