Harrasment over upgrade

Could MTN please remove me from the following two numbers that are constantly harassing me about an upgrade. *** & ***, I am BUSY at work and don’t have time for these calls. I sometimes get about 3 calls in one day. Your customer service department is fine with me being contacted constantly and stated there is nothing they can do about it. I am sure there is as my number has been handed over by MTN. If this is not done I have no problem converting to a pre-paid or another service provider. Annoying to say the least! Refer complaint query: 406729 & 403092