Treated unfairly

I have just renewed my contract and i was offered only 5g for the next 24 months. I have been with vodacom for almost 20 years, i have more than one contracts and I just realised that vodacom is offering other customers 10 g of data fpr the next 24 months even though it is their 1st upgrade. Why are the loyal customers being treated unfairly. What do we have to do in order for us to qualify for the 10g. Our loyalty is being taken for granted.