MTN a no-call centre

I have spent more than 90 minutes during the last 4 hours, making 5 different calls to MTN, but yet to have someone answering my call. The call automatically disconnects after about 30 minutes, sometimes after 2 minutes. Very frustrating and annoying. The reason for my call is that I received a text message earlier today stating that I am now on international roaming - presumably I have requested this, but I have not done so at all. I want to have it reversed, or at least an explanation as to what is going on? MTN please. I have been your loyal customer since cell phones were launched in SA and I expected better service from you.