MTN Caller Notify annoying Pop-up

[Zangletech]

Hey guys, can someone help me oh how to disable this annoying popup, every time I call my gf it comes up and it happens on her only?

Call 0 Message

Happiness is blah blah. Suffering is blah blah

Brought to you by MTN Caller Notify, dial *156*36#

I tried calling MTN they simply can't take it off and there are no subscription
It's so annoying thank you.

 

[Hemi300c]

Sorry to hijack but the other one:
You'll receive ___%discount

Also pizzes me off