Requested monthly invoice for November 2015

I have an open contract with MTN of which i am supposed to receive my monthly bill invoice on the 25th of every month. I have requested for my invoice for November since the 27th and their call centre have repeatedly said that i will get it the next day. Yesterday I even phoned their head office which i was transferred from one person to the other until the phone was eventually cut off. This phone is used for business and the costs are refundable every month of which i should have been refunded in November but due to no invoice its at my cost. On the 30th of November we experienced a house ******* of which our cell phones were taken, i called the call centre from 22h00 to 01h00 so that the cell phone can be blocked since its an open contract but there was no response from the call centre. I had to go to MTN Carnival for help the following morning.