Automatic payment

Hi, I bought a SIM card when I was in the US for 5 months and I also had an automatic payment for every month but when I come back from the US I forgot to cancel it and there were some other payments for the next months. The last payment was December 2019 and then I just blocked the automatic payment from my card and after a few unsuccessful payments, it seemed like it stopped. I just want to make sure if this and not using the number is enough for AT&T to get to know that I won't be using the number in future (last time I used it was December 2019) or do I have to do something else? No other payments are coming to my card but I just want to make sure it won't happen and I want to get them to know that I won't be using the number.