My phone was given to a stranger

I went shopping on the 15/04/15 during my lunch and as I fitted a shoe I forgot my phone on a table and I asked the employees there and was told they didn't see it. I went back to work and called they asking if maybe after I left they found it, to my surprise I was told \the owner to the phone took it". When I knock off I went to the store and the manager told me that it was a mistake it happened quickly so these nothing that they can do and they don't have cameras in the store. On the 17/04/15 I called the head office and after a week as I got no reply I called and again only to find out the 1st time I called they didn't lodge a complain"