Is Vodacom *****ing your data too?

I use data ONLY from Vodacom on a USB attached to my laptop. I have a query but cannot get an answer because your online Agent cannot communicate with me via Chat. I hold on for a human agent to answer but it always times out and I’m told to call your number !! If this complaint to Hello Peter is the only way I can get an answer then so be it. This is my question. I always buy 10GB data each month. I have been told that this data will last 2 months, but whenever I have data left over after 30 days, my data EXPIRES. Will you please tell me why Vodacom ***** this data from me. Or maybe I must just send my complaint to the relevant authorities. My cell number is available to you in this complaint. Thank you