Log into your self serve and check your detailed pdf ebill. Check the last 2 ebills. Was there a note that says an increase in price to a Long distance add-on? 

@Cheetah In your last month invoice we have provided an update that the price of this feature is going to increase. This is the content of message on your invoice:

Update to your 1000 International Long Distance Minutes feature.

Update to your 1000 International Long Distance Minutes feature. Starting in March 2022, your feature rate will increase from $0 to $3. In accordance with the service terms, you accept the change by continuing to use the service. If you do not agree with this change, you may cancel your feature without penalty within 30 days of the effective date of the change.

I hope this help provide some context. 

How do you cancel

Do you mean to remove the  1000 International Long Distance Minutes add-on?

Then log-in to your self serve  > plan add-on > manage add-on > remove it