Prepaid, charged for incoming unanswered calls

[John Doe]

Voicemail disabled. Texting disabled.
Being charged for incoming unanswered calls.
I tried Airplane mode, still charged.
I tried powering down the phone, still being charged.

I am on the $3 per month plan, for 30 minutes plus $.10 per additional
minute. The first 30 minutes is not rolled over, but money deposited
into the account is supposedly rolled over without ever expiring.
Unfortunately, the money I unwisely deposited into the account is being
picked at every single day even though I make no calls and answer no
calls and no calls go to voicemail and there is no text messaging, even
when Airplane mode is enabled and even when the phone is turned off.

Question: Assuming there is no solution to the problem... How will T-
Mobile charge for unanswered incoming calls when the allotted minutes
have been used up and there is no money in the account?

I don't mind being charge $3 per month for nothing but easy access to a
phone. But I do mind being charged more than that.