There’s like a 99% chance that they’re just blowing smoke (espesh since you weren’t even home at the time), but that is theoretically possible depending on your browsing habits and security hygiene. Keeping location services etc. turned off is a very good idea; here’s some more for-your-peace-of-mind pro jamer tips:
* Make sure all your passwords are random alphanumeric strings or (wherever possible) multi-word pass phrases, never ever re-use passwords, change them regularly
* Use an adblocker, flash blocker, script blocker, and VPN whenever you can (Opera, the best browser ever, does all that stuff: https://www.opera.com/ )
* Install antivirus software that’s actually good (https://www.malwarebytes.com/) and keep it up-to-date
* Don’t click on links you’re not 100% sure about
* Think real hard about what personal information you’re willing to share online
Speak Up and Stay Safe®: A guide to protecting yourself from online harassment (Feminist Frequency)
How to remove yourself from people search directories
Riseup.net’s digital security basics
Cybersecurity for victims of stalking and domestic violence (Hackblossom)
Stay safe out there, console cowboy