Unreliable,************* business practices

I upgraded my contract with mtn on 29/10/2019.I was supposed to get promotional data of 30gigs as per advert. Since then I've been waiting for the data. I've contacted call center several times and their answer is that they don't understand why I have not received data. I have sent an email to their *****center ,I always get reference numbers which serve no purpose. The cell number that I upgraded is ***.