Replacement phone

I took my phone Samsung S3 Mini on 12/11/2014 to Samasung Care Centre Woodmead because it was giving me an error message that it was not registered on the network, Reference number:***. On the 29th Feb 2015 I went back to enquire about the progress of the repair because I was not getting any feedback, to my surprise I was told they could not locate/find my phone. A manager by the name of NINA made a copy of my service document and promise to call me once they have located my phone. On the 10th June 2015 I went back there again after I received no feedback. I was told by a supervisor that they have not located my phone and that the same manager: NINA told them that she has lodge a claim with their insurance company and they are waiting for a new phone from them and that they will courier to me once they have received it. To date I have not received my lost phone while it was in their care nor they have contacted me to inform me of the progress with their insurance company. I am really disappointed with their service. I have nowhere to go.