Sending drivers with faulty devices and then not rescheduling deliveries

I ordered a phone through MTN that was delivered to my door on Wednesday. However the driver could not give me my phone as the biometrics could not be done due to a faulty device his office gave him. He phoned the office and they confirmed that they knew the device was faulty and he told them to move the delivery to Friday. So yesterday I saw a missed call. Sitting with a sick child i forgot to call back. Not 1 more call was evwn received. This morning I called DSV to find out what time my delivery will be here as I am specially waiting on my phone as I need it urgently. They said it is not booked for delivery as I did not.answer my phone yesterday. They seem to think 1 phone call is sufficient. I told the lady the driver spoke to the office on Wednesday and they promised i would have my phone today. They just keep on with its not happening. They cant do it today. I would have had my phone wednesday already of the office was not neglegent to give the driver a faulty device to deliver my phone with in the 1st place. Im not waiting a day longer. If my phone is not here today MTN is loosing a few customers as my entire household will cancel.