MTN not providing what they advertise

I recently upgraded my contracts with MTN and once again like many times before I don't get the complete data package as it was advertised at the time. On my data contract I am supposed to recieve 20GB anytime data and 20GB night express as well as some music and video streaming bundles. It is the second month after upgrading and I am not recieving the 20GB night express bundle. As mentioned already this is not the first time I have this type of issue after upgrading. Why can MTN not simply provide what they advertise?