Samsung s4 went missing at brooklyn mall samsung

I gave my Samsung s4 galaxy white in for repair of the lcd about 7 weeks ago... I filled in all the forms and give in my phone then after about 3/4 weeks they emailed me the phone is ready for collection, so I went on the sunday 22nd feb 2015 I got my phone back and turned it on screen was working but the touch wasn't after a few seconds the touch stopped working ... so I filled in some more forms and gave it back for a rebook... the Tuesday 24th feb they emailed me again and said my phone is ready for collection... so again I went to Samsung Brooklyn when I got there I saw all the staff wondering around as if they didn't know what they are doing at work... very poor but that isn't the point I gave my imei nr and name to them and they could not find my phone in collection files or the pending files???!!!!??? how does that happen??? im not going to leave it here if my phone is gone I want a new one there will be proof on the cameras that I were there that day for my phone please contact me before I go to the police to take further steps !!!