Vodacom-Unfair Chargers

Yet again Vodacom disappoints me. I have 2 mobile contracts with Vodacom for over 7 years. For the exact same data and minutes bundle, Vodacom chargers me different prices. On my 1 mobile number I'm charged R12.50 for a daily bundle and on my other mobile number, for the exact same daily bundle I am charged R5.50. It just don't make sense why the exact same product cost more. It goes to show that you can be a loyal customer and still such service providers will find a way to out smart the consumer.