Horrible experience with FiOS customer representative

On June 25th, I called to terminate my FiOS service. I spoke with an agent and asked, directly, on what day I needed to have my service terminated in order to not be charged for any additional days of service. She told me that my service ended on the 26th, and thus I asked to be disconnected on the 27th, therefore, to my understanding, not incurring any additional days of service.

I repeated my request - that my service be disconnected such that I not be charged for any additional days - at *least* one more time during the conversation.
I received an email saying that my service would be disconnected on June 27th.
When I woke up the morning of June 27th, my service was in fact disconnected.
On July 28th, I received an email bill stating that I owed $90.65, a month of service. In fact, this amount was at this point a month overdue. The bill for the previous month - dated June 26th - states that I was being charged for service from June 27th to July 26th. This bill is clearly in error.
On July 30th, I called Verizon and spoke with a woman named Pamela, who told me that I was charged for the entire month because my service had continued past midnight on the 26th.
I explained my case and I asked her if she had the authority to delete that charge. She said no, so I asked to speak to her manager. She told me that the email alerting me that my service was terminated on June 27th was final, and legally binding. I found this more than a little bit condescending. I asked again to speak to her manager. She put a "Ms. White" on the phone, who reported to me that she was in Hamilton, NJ. Ms. White told me that she understood my interpretation of the phone call I had on June 25th, and offered to charge me only for the day of the 27th.
I responded that I should not be charged for *any* days, because I had requested my internet to be disconnected at the end of my preceding month of service.
She refused to adjust the charge further. Further, she threatened me with un-doing the charge if I complained to anyone besides her. She said that I must accept the reduced charge she offered, and anything else would require an online complaint, upon which she would remove the reduction that she had agreed was due. While the reduction was, according to her, on the merits of the complaint - she said that I had been misinformed - her threat to undo the reduction is apparently out of spite. I told her to carry out the reduction, and she repeated that she would un-do the reduction if I complained any further.
I am now filing a further complaint, about not only to the error of the original charge, but also the dismissive and spiteful way I was treated by Ms. White. I really do not understand the need to cling to the charge, and I certainly do not understand the need to threaten me. Is this standard procedure?
I can *completely* understand how the first person I spoke with, on June 25th, made an honest mistake. I can also understand how Pamela can refuse to un-do that mistake, being a first-level customer support representative.
I was upset by the fact that Pamela decided to lecture me that the email I received stating the termination date (but not what charges were implied by the termination date) was somehow evidence of my responsibility.
I am *beside myself* at the condescending and combative manner in which Ms. White treated me.
I enthusiastically encourage you to review the recordings of both phonecalls.
In summary: I asked on June 25th, specifically to have my service terminated in such a way as to generate no further charges. It is my understanding that, if the service had been terminated at 11:59:59pm on June 26th, that would have been the case. Instead, it appears to have been disconnected at some point during the morning of June 27th, thus generating a full month's additional charge. I ask that you delete this *entire* charge. I refuse to pay *any* additional charge for a service I did not ask for and which I did not use.
This is, indisputably, a case of error on the part of your corporation. Even without reviewing the calls you can see this to be plain as day: Why would I ask for service to be terminated only hours after it generates a full month's worth of charges? As a result of this error, you delivered no additional services, but charged me for a month of additional services.
Re: Horrible experience with FiOS customer representative

Hi aaronbverizon,

Your issue has been escalated to a Verizon agent. Please check your Private Message Inbox for a message from Verizon_Support. You can find your Inbox by clicking on your username at the top right corner of this page. Please direct all correspondence concerning your issue to the agents who will be assisting you privately.