Phone removed from multi-line plan. How do I make sure that it is no longer charged to my credit card?

Thanks for the reply. So here is some more info...

The phone in question was on the same credit card account as the multiline account, even before it was added to the multi-line account. I removed it from the multi-line account and the website mentioned that it would become a single line account on autopay. I am assuming that I will now get an autopay charge on the multi-line account and also this single line account. As I mentioned earlier, the phone is completely dead, the sim card completely dead and I have no way of working on it via the website because of that. I am in enough trouble with my wife over getting our son a new phone, so that if I can't stop this extra autopay charge, I AM DOOOOOMED !!!

If the line is still being paid for, the sim card is not dead. Try putting it into another phone so that you can receive the text needed to reset the password. Once you can log into the account, just turn autopay off.

I am sorry for the tone of my earlier responses and I should have been more specific on how the phone was destroyed. My wacky teenage son threw his old crapping out iPhone 5s into our fireplace (with a fire burning) in a fit of rage. As I mentioned earlier, I was able to remove the phone/line from our multiline plan. Then I tried to log onto that phone/line through the ATT Prepaid website and was unable to since I forgot the password and of course was unable to reset it as the phone in question was destroyed.

It is now 18 days since then and no charges have showed up the linked credit card nor any other credit cards I own. Is it possible that the reason no credit card charges appeared is due to the phone and sim card being physically destroyed and also that phone could not be contacted by the ATT system?

Again, I am sorry for being upset and thank you for your responses. As it stands now, I have made sure that I have synchronized the ATT Prepaid passwords for all 4 phones on my plan and have documented them in my password book.

Regards,

Peter