Depleting data at lightning speed!

Vodacom just cant seem to get it right. My data contract recently expired and since then, my allocated data is deleted without any rhyme or reason. This is probably some malicious and deliberate attempt to force me to sign a another contract, which I am not sure I want to undertake, given the poor service I have been subjected to. Whenever I have run out of my allocated data, I have on several occasions loaded additional 500 MB data bundles -This is usually depleted withing a day or so which is INSANE?? I recently queried this with their contact Centre- after numerous failed attempts and several calls that were disconnected by agents, I was EVENTUALLY assisted by Eltino who had advised that something called VLite was depleting my data and that my account had somehow defaulted to VLITE. He also confirmed that when I had reported the matter previously, everything had been disconnected on my account. He duly corrected this but it would appear that I am back to square one and that the solution was short lived. Can someone please just get to the bottom of this and provide me with a tangible solution and some sort of explanation. I am seeing red!!!!