MTN deliberately blocking Number porting

Our Company has a few phones and due to very poor network coverage and indifferent customer service we provided notice over a 6 month period of our intention to move our business to their competition. As the time came closer, we provided more letters of our intention to port etc.<br> <br> They have now cut off all our numbers and told us that they are gone forever. They seem unable and unwilling to assist in moving these numbers to prepaid and have a totally inconsistent response every time we call, which obviously has to go through their call centre. <br> <br> This is costing us a lot of money and we would have made our intentions clear from the start and in writing numerous times. They are completely failing to follow through on their side despite many efforts on our side to follow up.