Cancellation Issue

I paid my bill for March on February 27th. On Friday I called Cox to schedule my Internet to be canceled on the 30th. They made a mistake and turned it off immediately. 10 minutes later I called them again and they turned the Internet back on and told me it is scheduled to be canceled on the 30th. I did not receive the order notification that it was scheduled to turn off on the 30th, rather, it says the 8th. I just received a bill for $43.33 due on March 23rd. I've already paid for March ($50), and owe nothing to Cox at this point. What am I supposed to do at this point? This is honestly amazing how bad support is. Do I need to get an attorney involved?