MTN IS GETTING GREEDY - ISN'T THERE SOME RELIGIOUS LAW AGAINST GREED?

MTN is sending far too many promotional sms's to my phone. I have tried to find a way to stop all promotional material but they make it almost impossible. Even when they send a message that includes an OPT OUT with the number *135# - if you use this number they send another message : Invalid Code *135# Please send ? to 686 for a complete list of valid short codes. When you do that, all you get back is: Codes: CS CSTEST Send CODE ? to 686 for more info 1/1

This is utterly ridiculous and designed to prevent people from finding a way to stop all this junk maiL they send us.

WE PAY ENOUGH ALREADY - THIS IS JUST GREED.