Unfortunately you are the victim of an attempted scam.
There are two Four Seasons hotels in Istanbul, I have called both and they do not have anyone by that name staying there, however they have had calls from other concerned people asking if someone there is in need of help.
You can read more about this type of scam here:
--------------------Your satisfaction is my priority; Kindly take a moment to rate my service 5 stars at the top of your question page so I am rewarded for my time; tips appreciated :)You can always reply back at any time if you need any further assistance at all.Pete.--------------------
Hi again, thanks for your comments. The photo could be fake, or it could have been copied from a website.
You could always post it on your Facebook page to warn others and see if anyone can identify the person.
The UK cellphone numbers will not connect, so they may have been disconnected.