Disappearing cellphone.

I took my samsung Galaxy 24 mini into the Samsung shop in Cresta (Sat 24/05/15) as I could not get the phone to switch on. I was informed that I should take it to the Samsung service desk at Dion Wired. I handed my phone to the person at the service centre and was told that the software would need to be reloaded. After unsuccesfully attempting to reload the software, I was told that the device would require a new motherboard and I would be contacted via SMS when it was ready for collection. On Sat 30/05/15 I decided to visit the store as I hadn't heard anything from them, only to be informed that the service desk had closed and that they had no idea how i could trace my phone. I then called the Samsung helpline to enquire how to trace my phone. I was told that it would have been sent to the Woodmead service centre and to collect the phone from there. I called at the Woodmead centre this morning to discover that they had no trace of my phone and had no idea where it could be. I consider this a disgusting incident as my phone has disappeared and no-one is prepared to take responsibility for this