Stock not arriving

Hi there It’s been a month now that I have taken a contract with a Sony Xperia XZ1 which came with a PS4 throuFG Vodacom . The phone and contract was received and signed on the 9th of December 2017 up til today I havnt received my PS4 which I am paying for. They keep saying it’s Sony’s fault as they are waiting for Sony to send the Stock. I honestly don’t know if this complaint will even help me but it’s really unnecessary for me to be paying for something I don’t even have possession of. Iv been to the Vodacom store in Durban, Pavilion shopping centre where I took out my contract and they were more than helpful to sort the contract details and other stuff out the staff are really helpful ...although I have been to that store countless times in the past month and all they tell me is that they waiting for stock from Sony and Sony is not sending the stock quick enough my problem is I am paying for something that I do not have use of. Why advertise something when the stock isn’t available and the store told me in a weeks time it will be here and Il be sorted out it’s been wel over a month now. I understand it isn’t the Fault of the the staff that works there but as soon as my contract was signed and I’m being billed well no interest has been shown to get me the product that I am paying for. Regards