Normally, you do not blindly believe a sat navigation sending you to that pond ahead at the end of the road. Similarly, tracking systems of public transportation have mostly supplemental value. From people who understand them more in depth I know that many scenarios of incorrect indication can happen:
- the vehicle broke and but it remains assigned (logged in) to the route by driver's mistake
- a spare vehicle is doing the route, but it is not equipped by tracking system so you do not see it coming
- the driver mistakenly signs their vehicle onto improper route
- the dispatcher mistakenly assigns incorrect vehicle for given route
- some other cases (related to various technical details)
This way, you can sometimes see hilarious things how a streetcar (a tram) is approaching your stop using a street without tracks - because a backup bus has been sent as a replacement and the data are de-facto correct. So take these trackers with a grain of salt.
Of course, in situations of true mistakes, the vehicle is improperly indicated also at the central dispatching, but this is not a big issue: If this comes into their attention, it can usually be fixed by checking with the driver directly, and rectifying the setup.
In whatever public transportation systems this happens and you need to reach out, you typically prefer contact numbers for central dispatching if listed publicly (some providers in my country provide them). If not, you pick something closely related, like a general customer line and they can contact the back office to obtain the proper information for you.