Horror MTN non existent service

Horrible MTN service : Took a data contract for 20 gig. To my surprise on 27 May and today I only received 10 gig. Surprisingly I got an SMS stating that my monthly 20 gig was loaded today. Tried to call their so called service champions but they terminate the call before you can speak to anyone. They are making me miss Telkom and that in itself sets the bar very low.