Vodacom Data usage even when router is off

For the past 3.5 months I have been complaining about disappearing data on my Vodacom data line. Everytime I call Vodacom they logging a call with a département that deals with the matter and will get feedback in 48hrs. Last one was 2nd June to date still waiting for 48hrs to get feedback already lost 0.45GB data since 1st July. The router has not been switched on still but manages to use data.