cant get to speak to a team leader or clarity on my billing

<p>I have got a Samsung S5 phone which is due for an upgrade. I received a phone call last week on the 11th of the month to upgrade. A deal which i must say was unbelievable which I took and upgraded. The reason I upgraded then was due to the fact that the billing date closes on the 11th of the month and should be pro rated for 1 day. I received my bill today via sms and it does not show how the figure was arrived at. I phoned the call centre and tried to speak to the lady and tell her my problem. She was not answering my questions and then I asked to speak to a team leader which was not forthcoming. I have been an MTN client for over twenty years. Why is it that when you want to speak to a team leader no one is ever avaiblable. They are always in meetings. It would be appreciated if someone could contact me and and furnish me with some clarity on my account.</p> <p> </p>