Reverse the charge with credit-card bank. Call comcast at your convenience or wait for them to call you to adjust your service/cost downwards so it meets your approval. If you have TV consider the free HD-DTAs that you get with limited-basic/choice-tv service-level.
There is no need to pay more than $0.00 (zero point zero) for voice-calls anywhere on earth. You don't even need phone-number(s) to do it - can use email addresses instead. You can do audio-only or video too. It's always free with facetime or skype or google-duo (if the data is going over an unmetered or free/already-paid internet connection.)