Very confused about the billing

I need someone to explain how the billing works.  I am set up for auto deduction on 10/28.  So my bill was paid.  The PDF file of my bill said it was for services from 10/6-11/5.    When I looked at my data usage, it says that my data usage is for 10/1-10/31.  Then I got a notice that I went over my data limit.  I figured that was wrong, because I just paid my bill on 10/28 and the data should have started over.  Which now confuses me even more since it doesn't end until 10/31.  Why do none of these dates line up?  If my bill technically ends on 11/5, why wouldn't my bill be due closer to that date?  Why is my data usage not the same dates as by bill?  This is just so confusing.