Mistakenly charged twice

Hi, I changed my plan one month from the 45$ plan to the 65$ plan. Below is how it went

1. August 8th: Renewed auto-fill -$40 (Regular)

2. Sept 3rd: Changed to $65 plan  (did not setup autofill, intended to have this plan only for one month). Next renewal on Oct 2nd. 

3. Oct 1st: Logged in and changed plan to $45 and set-up auto-fill

4. Oct 1st: ATT automatically charged $40 again on the same date and my balance shows as $40 now.

Does this mean that I don't need to pay for November? That is OK. When I paid twice it confused me. The auto-pay on Oct 1st should not have happened.