Verizon review: International plan

I was told that I would not be charged for calls from cell to cell if I had the monthly plan. I was charged nearly $400 for calls. They were supposed to look into the issue and never got back to me. I was told that they would not shut off my service while they were looking into it but they did. They offered to give me a credit of $150 but subsequently denied it. They refuse to allow me to hear the recordings or tell my why the charges were denied. They have people answering phone from different countries who provide wrong information that the customers rely on. It is almost impossible to speak with a supervisor. I thought we had reached a resolution only to find out they changed their mind and will not issue a credit. I should be credited the entire amount of the charges based on my reliance on information from their employees. I cannot get anywhere with them. I would like to try informal resolution before I take legal action. I question whether the misinformation is intentional to charge customers more money. I have seen several other similar complaints.