Charging despite not using account while abroad

I am an international student who studies in the US. In January after I had been at home (in the UK) for Christmas break, I discovered I had a $173 bill to pay for December and January and additional fees to reactivate my card, since I had not used it for around a month. Now, I am back at home due to the COVID 19 outbreak, meaning I will not be using my American AT&T account for a while. Does this mean I will be charged again when I'm not using it and also charged to reactivate the account? I just turned data usage off in the settings, does this help to avoid being charged? What else can I do to temporarily disable services and avoid being charged?