I've been seeing this for a while now and haven't been able to ask the community about it.
So for a while, i've had account credit / balance randomly taken away from me? Every so while, i've been losing around $3 for some reason and it isn't telling me what it's for.
When I was overseas, I just ran out of data for a 1 day plan, it charged me $10 immediately without me knowing or confirming then another $3 was also deducted from my balance making me very confused.
Every so while, $3 keeps getting taken away with no information regarding why it does that.
Also, randomly I had wifi enabled for a while and it was using my data for some reason? I was connected to Wi-Fi the whole time and all of a sudden i get a message saying i'm running low on data?
I need some help, I keep losing money from this and it's really frustrating without me knowing why it's deducting balance.
Best port of call would be to call 777 but from what you've described sounds like you're buying a 300MB 1-day bundle.
The $10 I'm not sure about but could be casual data use.
Definltely sounds like your're using data despite Wi-Fi being on, what phone do you have?