Forcing me to listen to an add when I make a call

I am on contract and when I make an outgoing call MTN is forcing me to listen to an add for some MTN service.<br> I find this a disgrace, and a waste of time. I will move my contract over to another carrier as soon as it expires. I already have to receive a constant bombardment of SMSes that I never signed up for advertising MTN **** or some life insurance or whatever. Now having to force me to listen to an add before I make a call is the last straw.<br> Cheers MTN