Promo data stopped

For the past 3,5 years I have received a so-called promo 20gig data per month. After an upgrade. I queried it at the start and was told "our loyal and good clients receiving it" Same with my wife. We upgraded again and again queried and the consultants said they don't know what it is. Suddenly last month, without any warning, the data upload has stopped. Upon querying why no warning or notice period I was told "sorry that's the way it works!" Wow Mtn, where's your decency to at least warn your customers, after 3,5years that you are going to stop this?!