I called my parents living abroad using FaceTime on July 31, and throughout the call both my parents and I were at home and connected to WiFi. After the call I got a message from Verizon saying my account "has reached $236.55 of additional International Long Distance calling charges which will appear on your next bill 08.03". I thought this didn't make any sense, because I've used FaceTime both on WiFi and Cellular Date to call my parents and never seen such a bill before. So I called the customer service on Aug 2 (which is before the bill date, Aug 3). After waiting for nearly two hours, the representative said that he couldn't see the charge yet, and there's nothing he can do before the bill is posted. He suggested me to call back later.
So I call the customer service again on Aug 6 when the bill is posted, only to to be told that I should've called before the bill cycle ended and added an international plan to cancel out the insane charges. But I already called before the cycle ended and was told there's nothing to be done at that point and that I should wait for the bill!
Given what happened, can I add an international plan retroactively for just a month? I've looked through the Verizon website and app, and it's really not clear when the effective date of the international calling plan is. Does it last one month starting from the day I add the plan, or will it cover the current billing cycle (including previous calls made within the billing cycle, which is my case)? Unintentional international calls seem to be a very common problem, especially with FaceTime, and one can not make informed decisions if the rules are not clear from the Verizon app to customer service representatives.