MTN MENU POP UP MESSAGES

Promotional POP UP messages from MTN MENU!!! Please remove them! I get them daily and no one can help!! Example :

Y'ello, Double your Bundle. Get 200MB MTN Data FREE, buy 200MB for R29 valid for 7 Day. Dial *142# and select 'DOUBLE DATA' to buy this offer. Ts&Cs apply. This is another: Y'ello! Have tons of fun with MTN Play! Visit www.mtnplay.co.za and experience a new exciting MTN world of Music, Gaming, Video and Lifestyle content. Ts&Cs.

I've been a client for over 20 years so don't make me change to Vodacom as a result of these! I have never received these SMS's before! Why now?????