Billing

My promotional was up in July. So I canceled my cable services on 7/17 and got flex. Paid final bill on 7/19 because next billing cycle starts on the 20th . Now Comcast is still charging me for cable services I don’t have. Comcast is trying to tell me My final payment takes 24 hours so I missed the deadline. Wow. My final payment was automatically deducted so what is Comcast doing? I have to pay for services I don’t have any more. Comcast is crooked !!