Stop MTN promotional spam messages!

I am constantly being bombarded by SPAM pop-ups on my Samsung Note Phones (Yes more than one). The message bypasses and unlocks the screen lock which causes one to accidentally click on the OK option which in turn agrees to the Opt-in at a set price per day / week or month. I then realized the issue when the phone sent me a message stating that "you have started incurring costs" Called 135 was told that I can cancel by dialling *155# and then cancel the service, also disable the WASP options / subscriptions from here. Problem is they immediately deduct the money from your account. Once cancelled you are informed that the subscription has been cancelled, but.. they already have the money. The amount is not the issue here, but just imagine a few thousand people making this mistake a day and how they are exploiting the system to generate quick cash in this manner. (My opinion, anyway, I digress) I called again asking how, can I, DISABLE the pop-up SPAM messages all together? I was told, there are specific mobile menu options that have to be disabled and was transferred to another department. I was instructed to open the "MTN MENU" on the phone, select the "MTN MsgXpress" option and disable the messages. Problem is, it was already disabled. Still the pop-ups continue with “Spectacular” deals such as "R29 whatsapp bundles for 7 days" and "R4.50 p/d for Music streaming" ETC. I already have a business contract, NO NEED FOR DATA BUNDLES! With no way to date as to how we can disable the MTN SPAM SOFTWARE to stop unlocking and tricking us into accidentally clicking on the spam of the day!