Vodacom 2GB data disappears

I have a prepaid account for 4GB data per month. 2GB goes on, on the first to one number and 2GB goes on the 13th to another number. I have had this for several years and have become concerned how 2GB is used faster and faster without me changing my internet use much.<br> <br> Several times this last year 2GB has disappeared in 3-4 days. I had my computer checked. I have no updates on, I am the sole user of it. I do not do much youtubes etc. I was told those are possible reasons why, so I have been super careful. This Dec .1st my 2GB were used up in ONE Day! Now I know it is not my usage. And I was online little that day plus I had leftover data from previous month. When I call the customer help, waiting often 20 minutes to speak to someone, the minute I mention data, they hang up the line. This has happened 4 times.