Wrong iPhone being sent to me

On Friday, 27 September 2019, I ordered an iPhone 11 Pro 64GB for R779/month via the Smart Device section of FNB’s website while on the line with one of FNB’s consultants. I was pre-approved and everything was good to go, however, the consultant said that they were unable to complete the order due to there being no stock available. She said I would get a call the following week to complete the order, as physical stock had to be available in order to do complete it. I have a screenshot of the completed order as well as a reference number for that call. On Monday, 30 September I received the call that was promised to me and I completed my order for an iPhone 11 Pro 64GB for R779/month over the phone with a consultant. They advised me that I would hear from the delivery company shortly, and all was good to go. However, I received an email shortly after the call to confirm my order and to my shock the wrong device (a regular iPhone 11) was being sent to me. I have since wasted hundreds of Rands worth of airtime calling FNB over and over to get this sorted out. I have now been told that there were only 10 iPhone 11 Pro devices available for R779/month and I was not one of the first 10 customers to order it. This is complete nonsense, since I showed friends the deal 2 days after I initially ordered it. I have requested copies of the phone calls that were recorded, which is proof that you have not upheld your end of the contract, but your consultants are now ignoring this request and are not getting back to me at all. This is simply unacceptable. I ordered an iPhone 11 Pro device and this was agreed to by myself and FNB over the phone. You cannot send me another device because it suits you. I want the device I agreed to purchase for the price I agreed to purchase it at, and not a device of FNB’s choosing. I would also like the recordings of these calls so I can take this matter further for breach of contract.