Typically that upper menu bar will show app/service Notifications towards the left side, and phone features/Status on the right side. If you swipe downwards twice on the menu bar that should show an expanded icon menu list, including the visible icons with their names. Try looking there for that little green man icon.
If it's not the Mobicel Infinity, can you tell us the exact brand name and model name/number? When I searched "Mobi infinity," I couldn't find a specific phone with that name.
The phone could have come with a step counter preinstalled, so even if you didn't install one yourself, it could still be on there.