bad service

My name is Elton. My sister Michelle took out a contract with Vodacom. I am paying the contract. Last year I upgraded to Samsung S6 Edge. After 1 month phone gave problems. As I am busy working I never got around to take the phone in to Vodacom. In December I went there, so they informed me to bring it after the 26th as repair is closed. So I explained to the consultant that the phone loose signal and that I sometimes can`t make a call. I then need to take out the sim and reboot phone to make a call. Also the phone is freezing and reboot itself. The internet also sometimes does not work, so I also need to reboot the phone. So I told here that I want to book phone in for warranty assestment as I do not want the phone anymore. I ask here if they gonna replace the phone if I could take an iphone, she then told me she will try her best. I then told here that if not possible I will then stay with the Samsung s6 edge. The phone was then booked in the 04/01/2016. On the 07/01/2016 I received an sms stating that my phone is with Mosaelbay repairs and awaiting parts. So I phoned the consultant here in Beaufort West about the sms. She then informed me at that moment that Vodacom do not do wa