So after being told my Sunday Ticket Max would be free this year, and after getting a credit for the first installment I was already billed, I got charged for the second installment of ST on my September bill.
I called again today and got a credit for the 2nd installment I was billed, along with an assurance that I would not be billed again for ST.
For all of you who were told you got ST "free", I highly recommend you check your bills every month!