There’s a hardware issue. The only UL listed central monitoring services I know, even the $9 a month ones that work with self installed systems, require cellular or landline connection. No internet or WiFi, it’s just not considered reliable enough for fire and security.
This is typical:
Your security system is designed to plug into a device called an RJ31X jack installed at your premises on one of your regular telephone lines. When activated, a relay in your security system “seizes” your phone line and gives the security system priority use of this line, allowing the security system to report its signals to the central monitoring station using a toll-free number. Don’t have a landline? No problem. Most security panels offer a GSM cellular option (SecureLinc for example). These panels are compatible with this monitoring service.
This is the hardware piece a typical ST installation is missing.