LOST / STOLEN Phone tracking methods? android

Hi Guys, I have lost or had my phone stolen , am pretty sure it has been stolen however I am not 100%,

I attended a small party on the 13th of September, yesterday. from 7am to about 12pm It was my friends house and his mum and family where their I knew everybody but one person who lives a long way away, and I have my doubts that this one person has something to do with the whereabuts of my phone but I cannot pinpoint her or accuse her?

I let one of my friends use my phone at 9am which is all logged. on my network usage so I know he had it around that time he told me he passed it to me on the table which I think can remember him doing. I then believe I put it on charge but since then it has disappeared . I have been out with this guy lots of times and honestly don't believe it to be him if it was stolen. but this other girl I have my doubts.

Its a Samsung galaxy s5 I have registered the phone with Samsung and I have sent a message to my phone with a password on it. Each time I try to locate my phone it says unavailable and last seen 13th September.

I was sure I has battery in my phone but now its been turned off, goggle timeline shows the phone at 10:30am on google maps at the house the small party was, but this does not really help finding the phone. I didn't leave the house so its either in the house or stolen.

I don't know what else I can possibly try ? am gutted

thanks