Disappointed with MTN Data Promos

Yesterday on the 21st of January, I got data for R99, monthly combo 2GB plus 60 minutes. After recharging it, to my surprise I got 1.2GB and 60 minutes. I wonder where my 800MB went. I have been studying these MTN promos, they are **** or there is always a catch. It's better to charge me R99 for 1.2GB than sweeten the deal by convincing me that I am getting a 2GB where as in actual sense 800MB is being ****** from me. It is not good business practice for such a big company. I have proof to show. I am just disappointed with MTN, I never use their promo stuff, it is a waste of time, there is always a catch. I have never won anything even after being a loyal customer for such a long time. They should be clear with there promos.