So I am kinda new and confused

I just started service on 5 devices 4 cellphones and a watch I noticed my bill for 2 days August 27-29 was $506 and then from aug 29 to sept 28 I was charged an additional $567 right now my bill is sitting at $925 I was charged 4 activation fees when they were supposed to be waived due to union membership and upon further inspection of my past bills they claim my bill has been behind approximately 200-300$ a month that they keep adding to the next months bill... how is that even possible??? If I had a past due balance in that amount a month wouldn’t that cause them to disconnect my services (which has never happened) I was told my $120 in credit would take a few days last month they still haven’t corrected it??? Anyone else having these issues with this company? Seriously thinking of taking my service elsewhere....