Those work well and you can also get them that work off a cell phone provider; I used to have one that was US Cellular enabled. 

It's a little device you pair with your cell phone.

We go above and beyond when it comes to protection.. starting with insurance coverage, sings in the listing and in the property that there is no guard on duty (as silly as that sounds), putting extra locking device high enough so youngsters can't reach, an alarm/beep system to alert them that door opens for those with small children (or elderly) so they cannot wander out in the backyard with no one noticing and risk drowning.

I started my professional career in medical device sales and still do that full-time.

I will PM you my cell number and we can connect to brainstorm for your case. 

It might be worth talking to a lawyer but not sure if it's small claims or worth it.Also, you might already have all of these things but for future prevention:- smart thermostat (so you receive alerts when the inside temperature dips below whatever preset you have)- Minut (or similar device) would also alert you to the inside (and outside) temperatures; for example, I have 2 devices inside the house and outside on the hot tub deck.

I'll keep you in mind if I device to pull the trigger.

Door locks are all coded and changeable right from my cell from anywhere.

It might be a $50 unpaid cell phone bill from when they switched carriers.

I recorded a virtual tour on my cell phone because I was getting tour requests I couldn't fulfill, but no one has asked to see the property since I made the recording.