Why not just use Ubidots and send the status of your machine to a variable. Then you can set an SMS Text Message Alert with a custom message to let you know an error condition has been triggered on a machine.
Just trigger an SMS message to be sent anytime a variable goes over a certain number like 1 vs. 0, or any time a variable goes over any particular number.
This is better than just getting a phone call from a specific number because the SMS message will contain a specific message about what is going on.
You can trigger voice recording calls by interfacing with Twilio but that I have not tried yet so I can't say how hard or easy that process is. Ubidots is super easy for this.
I get an SMS message anytime my Electron's battery level goes below 22% - saying it's about to go into deep sleep mode, and then also when the battery is fully charged with a text saying the battery has been fully charged via solar power.
You can have it send an Email alert also which is free. SMS message cost a few cents after you go over the free SMS messages they give you.