Vodacom is riping me off: 1GData rip-off

I used to buy 100MB data and they used to last me for a month, I complained to Vodacom when the data started lasting for a week. I started buying 1G data that used to last me month now the 1G data doesn't even last for 2 weeks, I can not spend my money on data, Vodacom is ripping us off! On the 25th October 2017 I bought 1G data, a week later the data was finished, on the 3rd of November 2017 I bought another 1G data. It didn't even last a month, on the 17th Novemver 2017 I bought another 1G data today I get an sms that says I have less than 300mb on my 071 number. THIS IS MADNESS!! VODACOM IS MAD NOW. In less than a month I have bought 3G at R450 and still its not enough for FB and Whatapp applications only? I don't use other apps, and the apps have been not active for a while, I only use my data for whataspp and fb and I don't use you-tube or games or any other unnecessary junk on my phone. I don't download video, I only receive photos sent by my contact only. Vodacom is rippin me off... I can not spend so much on data alone, #Vodacomdatamustfall!! Vodacom I want my data back... ! I am fuming! I cant be offline because Vodacom just want more money from me, Vodacom just wants to rip me off!