Flooding own customer(s) with spam

What happens when you opt out of an MTN promotional service: (which you didn't subscribe to) - they add you to another list, then you opt out of that, then they send you THREE lists which you are supposed to be opting out of if you don't want the messages. How many lists are you supposed to opt out of? Hundreds?????<br> <br> I was very happy when MTN helped me to get my new phone and contract quickly, but this kind of MULTIPLE spamming is ENTIRELY unacceptable! Do they think customers have all day to sit and opt out of utter junk that they didn't want to be subscribed to in the first place?!!!!!