MTN Service Messages Inserted in to Private Calls

For the last 3 months I have had MTN LTE upgrade messages inserted in my private calls.<br> ie. I make a call and have to listen to a 20 sec MTN message telling me to upgrade to the new LTE sim before my call connects.<br> <br> I find this unacceptable and a complete invasion of my privacy. I am pretty sure it is also in contravention of the consumer protection act.<br> <br> I have tried numerous channels (phone calls, social media, emails) to get this removed. I was told by a customer service representative that they would request for my number to be cleared from some database.<br> <br> I am still receiving the messages. If it does not stop I will change service providers.<br> <br>