AT&T next issue extended Contract

[goofy810]

So I am on my 3rd ATT next phone started with the 5s then 6+ now 6s always do the 12 months deal and end up paying off vs truing in with no issues. This time I wanted lower bills so I did the 12 month deal with a down payment of $250 or something like that. My bill should have gone from $39 Next to $21 next so total bill should have dropped $18, boy was i shocked when I looked and found that they were charging me $40 a month for the line + my $21 for next payment. Another words they set me up with paying for next and a 2 year contract. I called to see whats up and the CS rep said oh no it takes a month to update blah blah and as a curtsey she would credit me the $25... um no not a curtsey I pay for the phone out right so should be paying $15 not $40 for the line. she promises its just due to this month and will be fixed next month. Has anyone ever had this happen ???