Unauthentic ,********* and questionable integrity at MTN

I have done a WIFI rooter application on 2 May 2019, apparently there was a promotion on data bundles,I was told that 40GB was R199pm for 24mnths contract,which I took a rooter and made my installment to be R239,which was 20GB anytime and 20GB night express, I then received only 20GB which 5GB is anytime and 15GB Night express, I phoned the consultant at MTN customer care and they promised that it's gonna be fixed permanently ,it was then fixed ,then the following month the same mistake again,I then phoned customer care again, I spoke to Nombulelo with reference *** on the 6th August 2019, she also promised that my contract will be rectified,but as I type in here, I'm still being credited 20GB instead of 40GB, the worst part is they give only 5GB for anytime, the reason I took this contract was the 40GB Offer nothing else, I feel like I was ****med by a huge company in the world, MTNs service in *********,unauthentic and questionable, this is not right and it needs to be rectified with the immediate effect.