SIRI can be set up to work from the lock screen. That is not the default setting and on this phone had not been activated. You just hold down the home button and, if activated, you can try saying "Call home" or similar.
Nearest Apple Store is Geneva. SIM card is from Swisscom. I'll try them next.
Oh, it's not a 5 it's a S, guessing 6S?
Could have been stolen and then dumped??
I'm beginning to think so. The SIM is locked, which normally you wouldn't find on a phone.
But I have now edited my wallpaper on my phones/iPad to add my land line. I recommend everyone does something similar. These things are not cheap.