Disgusting service

An experienced teller advised me on a brilliant mobile phone(ZTE) when I wanted to buy a Sony. Used the phone for 8-9 months and it just died. Took it in as it was still under guarantee which went for about 6-8 weeks without any feedback. They then called me to say my phone was ready, went there only to find out that it was not even tested in the store that it is repaired(using my own petrol), took it back the next day as I was advised to charge it. After another six weeks still no feedback or a courtesy call. My wife went to check on the phone as she was by the mall - she was advised that the is a ***** missing and it looks like the phone was taken in for repairs when they worked on the phone themselves the first time. Now how stupid can I be to repair a phone myself knowing it is still under guarantee???? Such a bad and ***ard experience I received from CNA and will certainly not recommend the store to anyone I know!!!!!!