MTN SUBSCRIPTION ****

I keep getting smses thanking me for subscribing to mtn services I don't click any links nor subscribe to any of them sometimes I get smes while I'm sleeping and my airtime dissapears. These are mtn services. I immediately unsubscribe and I have sent messages on Facebook because I can't get through to the call center they have been of no assistance. I told them I want to block any services I still keep getting subscriptions. If you do not assist I will leave this network and I have been a subscriber with the same number for over 10 years