Product: Credit card or prepaid card

I am writing to appeal the decision made by Citicards that determined two charges I  made on XX/XX/2019 for {$290.00} and {$200.00} to XXXX  XXXX to be valid. This is an outrage and I would have written sooner had I not been so dismayed and angry when I received the news. 

This is even more upsetting because only within the past three weeks, I heard a best friend in Maine and my cousins husband in Texas were scammed in the very same way. 

Here is a detailed explanation of what took place. 

On XX/XX/XXXX, I was doing a XXXX search ( for soap factories in XXXX in the late 1800s ) when suddenly my computer froze, a screeching, beeping sound commenced, a drop down screen appeared instructing me to call the 888 number provided to reach XXXX XXXX, and a digital voice announced that my computer was in need of technical assistance and I needed to call the 888 number immediately. My first reaction was to try to shut down my computer but I could not move the mouse. My heart beat raced and felt as if it was going to explode out of my chest. Not knowing what else to do, I called the 888 number. A kind voiced XXXX answered. I explained what had just happened and he promised to help me but in order to do so, he would put me in touch with tech support. The tech person introduced himself and explained I would need to purchase some software to help him remove the problem. This required me using my credit card for a purchase of {$290.00} and included a one-year service contract. I was still so upset and my heart was still racing that it took me several attempts to get the charge approved and processed. I then had to give my permission for the tech to take over my computer to search for the maleware, which I allowed him to do. Four hours later, he declared the problem was fixed, but then he pass me on to another tech rep. 

This man was extremely aggressive. He explained I still have numerous vulnerabilities and would need to purchase additional software for over {$500.00}. Because in my gut, I knew this was a scam, I stated firmly that I wasnt going to spend any more money. At this point, he became belligerent, pressuring me with the why and how I was going to have the same thing happen again. I again said I wasnt going to spend more money, and that I didnt really know who he was. He shouted, Well, I dont know who you are! However, I was tired, noexhausted by the strain of having dealt with this situation that when he offered me a deal, I agreed. They would reduce the price of this additional software and throw in another year on my service contract, all for only another {$200.00}. Once again, it took several attempts to get this transaction approved. At least I had my computer back. 

Shortly afterwards, I posted the whole situation on XXXX, and a friend of one of  my friends wrote : Take a deep breath, XXXX, but youve been scammed. This woman, who owns a professional XXXX service company, came to my home several days later to really clean my hard drive and explain how I had been had. Meanwhile, the so called service company calls my cell phone 8 10 times a day, every half hour, leaving a robo message. So they have continued to harass me, nearly ever day, for the past two months. Naturally, I dont answer those calls.

Summary of my complaint : despite my declaration to MasterCard that I approved these two purchases under duress, they found the charges valid, and I was forced to pay the {$500.00}.