Who I have the same questioned this topic

I am a very long time Verizon customer. For decades I used an outside company for my international calls and blocked any international calls on Verizon -due to the huge cost per minute I did not want to even make a direct call accidentally. In February i notice such accident still happened on one of my 4 lines and called to make sure all lines are blocked. At that time the customer representative offered me to enroll in an international plan that looked competitive to the one I was using. The 4 lines were entirely blocked for international calls. After a week and a close comparison of the rates I called Verizon to enroll all our 4 lines in the Global international plan with 2 cents a minute compared with 2.99 dollars a minute without a plan. That was about 150 times less of a cost per minute. After a month and a half  my bill came over $2600 , just to find out that the Customer Representative only moved 1 of my lines on the global plan. Instead enrolling all lines in the plan,  without my permission unblocked the other 3 lines and left them on the minute by minute international cost - WITHOIUT MY PERMISSION TO DO SO. After calling customer service I was told they will do an investigation and I will get an email with the result in 3-5 days , no email or text for 10 days. I called again and was told a supervisor will call me in 24-48 hours. No one called me in 5 days. How do I submit a complaint to the corporate office so it can be solved asap and have my account in order. I expect the next bill to be also oversized and the situation needs to be solved urgently. Thank you.