MTN sure knows how to dissapoint a loyal customer

In the second week of August, I upgraded my MTN contract, thereby renewing for a further 2 years. My new phone device was "delivered" on 20 August. On opening the package, I found that the incorrect device and sim cards had been delivered (Huawei P8 Lite instead of iPhone X) and that the P8 Lite was, according to the invoice, intended for a Mr Mosehla (although the parcel was addressed to me). I called MTN and was advised to return the phone to a MTN store, after which I would have the correct device and sim card delivered. I did so on 22nd August. I handed the hardware to Thabo Mpanza at MTN the Glen. He provided me with a Goods Received Note with reference number 1- ********** 8539. Subsequently, heard nothing further from MTN. I have since contacted MTN four times, provided copies of Mr Mosehla's invoice along with the MTN The Glen Goods Received Note and every time I call I get a different excuse as to why no new phone has been provided. Yesterday for example I was told to go to MTN The Glen AGAIN and get a copy of their waybill! I feel that I am being punished for a mistake that was not of my making. I have since paid a month into the new contract with the next debit order due soon. Please can somebody help me receive my new device. I have been a customer of MTN since the late 1990s and have numerous contracts. This has really disappointed me.