Robbing Clients of data

I still had small amount of data when realized that it was going to run out and be taken from my airtime if I do not re-charge. I then re-charged, but now my new data is being used, and the first lot is still sitting there which I will forfeit on 6/11. When I phoned the call center the man advised me that they use the last re-charge first, and that is their policy. There are millions of Vodacom users that do not know about this, and are just loosing their data on a daily basis. Vodacom does not care a shoot about their clients, they are only there for the taking. I do not care if it is 2, 5 or 10mg on my phone, I paid for it, it is mine to be able to use as I wish.