Vodacom Misrepresentation of airtime/data purchase

when dialling *135# and you are buying data. 500MB at R63. received 250 MB with a further 250 MB ("FREE" Night Owl Data to use between 00:00 and 05:00). It is a total misrepresentation of what Vodacom is offering. So now I have to buy R100 for 1gig to receive 500MB of data.... and 500MB Night Owl Which does'nt get used anyway and whatever data is left at the end of 30 days is lost to us as loyal customers anyway.