VODACOM

We have a Galaxy S5 mini on contract and the phone has been switching on and off as well as without touching it, it changes screens constantly and very annoying and difficult to use. The phone was taken to Vodacom Tygervalley and was sent to Johannesburg twice and came back both times with them saying there was nothing wrong with the phone. There is clearly a fault with the phone. We are paying for something that cannot be used and feel that no-one is willing to help and resolve this problem. Please could someone urgently phone Christine Nortier on *** to resolve this issue as soon as possible.