pathetic service

I renewed my cellphone contract in store with Pretty on 5th July. I asked for an iPhone 6 64GB handset as seen advertised on the Telkom mobile website. Pretty told me that 8ta doesn't keep stock of these handsets and that I can have a 16GB instead. I was concerned about the storage space and specifically asked him about it and asked if the phone would still run efficiently if I stored my photos, music and large files on the cloud (and just used apps). He assured me it would be fine and based on this advice I went ahead and took the iphone 6 16GB. 5 days later the phone told me I was out of storage (just using apps). I went into store immediately and spoke to Pretty and asked to return the handset and change my contract to the 64GB deal. After a lengthy wait, he told me that he would have to submit this request to their CPA department and that it would take 48 hours for a response. That same day I called the 8ta helpline and they told me that I could cancel my contract and go straight to the istore and order the handset through them with no penalty fees applying. 13 days have passed since my request to cancel. I have called and emailed 8ta almost daily and am getting no response.