Vodacom *****ing my data

I have been with Vodacom for 13 odd years & i have been that one that always says i get brilliant service & will never change....then i get gobsmacked by my data billing. i have had my vodafone wifi device for about 3 years with a 2 gig monthly data, so i know how to use it and i know how to ensure my background apps dont run. in the last 3-4 months my data disappears by the 7-10th of every month at first i thought maybe its me, i don't download or stream, i use it for social media odd personal emails and updates of my apps, if i check on the vodacom site i use no more that 1 gig a month. but recently its just gone, so this month i was travelling out of SA and my data device stayed home and i had my cell ph, so nothing was connected to the data, i flew out on 2/11 and returned 8/11 and what do you know my data is gone, finished but how if i am not home and noone else has access to it. i called 111 & was told my background apps maybe have been running, hello hear me i was not using my data where and how did it disappear and you can see by my cell acc i was not in SA. so a staff member is either *****ing my data or vodacom is, and i can see i am not the only one with this issue