We have have Verizon MIFI forever here and sometimes we get charges thinking it is was the current cycle and turned out to be the last cycle coverage.. Hard to tell sometimes which cycle they are billing...
Also although our MIFI is pretty secure it always bothers me being wide open to everyone in the camp grounds... We have everything password protected... Have had some folks asking if that protected WIFI signal was us after seeing us using our computers sitting in the outside easy chairs.. Never really have noticed anyone else on any of our billing using it but it is always a concern for me...
Our dataplan is a grandfathered 3GB dataplan and some months we just barely sneak by...
Roy Ken